diff --git a/cmd/server/chunked_load.go b/cmd/server/chunked_load.go
index 8acb5fd8..094375ad 100644
--- a/cmd/server/chunked_load.go
+++ b/cmd/server/chunked_load.go
@@ -124,6 +124,13 @@ func (s *PacketStore) LoadChunked(chunkSize int) error {
 	if chunkSize <= 0 {
 		chunkSize = 10000
 	}
+	// Startup-ordering invariant (PR #1643 R1 munger #2). Mirror the
+	// guard in Load() so the production async path also fast-fails when
+	// neighbor_edges has rows but the graph is missing. See Load() for
+	// the full rationale.
+	if neighborEdgesTableExists(s.db.conn) && s.graph.Load() == nil {
+		panic("packet store LoadChunked(): neighbor_edges table has rows but s.graph is nil — graph must be loaded before packet load (see main.go #1643 invariant)")
+	}
 	s.chunkedLoadInit()
 	// Reset state for repeat calls in tests.
 	s.loadComplete.Store(false)
@@ -193,6 +200,19 @@ func (s *PacketStore) LoadChunked(chunkSize int) error {
 	// that semantic by starting one below SQLite's minimum rowid (-1).
 	var cursorID int64 = -1
 
+	// Relay-hop fallback inputs, fetched ONCE before the chunk-query loop.
+	// getCachedNodesAndPM issues its own DB query, so calling it while a
+	// chunk cursor is open would deadlock on a single-connection SQLite
+	// pool. resolved_path is never persisted post-#1287, so scanAndMergeChunk
+	// re-resolves relay hops from path_json using these snapshots.
+	// PR #1643 R1 munger #1: cold load uses unique_prefix-only gate, so
+	// the neighbor graph is no longer consulted here (affinity-tier
+	// resolution against ≤168h-old observations would silently mis-attribute).
+	s.mu.RLock()
+	_, relayPM := s.getCachedNodesAndPM()
+	s.mu.RUnlock()
+	var coldLoadAmbiguousHopsSkipped int
+
 	for {
 		conds := append([]string{}, loadConditions...)
 		conds = append(conds, fmt.Sprintf("t2.id > %d", cursorID))
@@ -233,7 +253,7 @@ func (s *PacketStore) LoadChunked(chunkSize int) error {
 			return fmt.Errorf("chunk %d: query: %w", chunkIdx, err)
 		}
 
-		chunkTxCount, lastID, err := s.scanAndMergeChunk(rows)
+		chunkTxCount, lastID, err := s.scanAndMergeChunk(rows, relayPM, &coldLoadAmbiguousHopsSkipped)
 		rows.Close()
 		if err != nil {
 			return fmt.Errorf("chunk %d: scan: %w", chunkIdx, err)
@@ -300,6 +320,10 @@ func (s *PacketStore) LoadChunked(chunkSize int) error {
 	elapsed := time.Since(t0)
 	log.Printf("[store] LoadChunked: %d transmissions (%d observations) across %d chunk(s) in %v (chunkSize=%d, DB total=%d)",
 		totalLoaded, s.totalObs, chunkIdx, elapsed, chunkSize, totalInDB)
+	if coldLoadAmbiguousHopsSkipped > 0 {
+		log.Printf("[store] LoadChunked: skipped %d ambiguous-prefix relay hops (unique_prefix gate, PR #1643 R1)",
+			coldLoadAmbiguousHopsSkipped)
+	}
 	s.loadMultibyteCapFromDB()
 	// Mark complete on the success path only — see the function-level
 	// defer above for why this is NOT in a deferred call. Probes that
@@ -312,7 +336,7 @@ func (s *PacketStore) LoadChunked(chunkSize int) error {
 // scanAndMergeChunk consumes one chunk's rows under s.mu.Lock and
 // returns the number of distinct transmissions seen + the max
 // transmission id (cursor for the next chunk).
-func (s *PacketStore) scanAndMergeChunk(rows *sql.Rows) (int, int64, error) {
+func (s *PacketStore) scanAndMergeChunk(rows *sql.Rows, relayPM *prefixMap, coldLoadAmbiguousHopsSkipped *int) (int, int64, error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -411,6 +435,20 @@ func (s *PacketStore) scanAndMergeChunk(rows *sql.Rows) (int, int64, error) {
 				rp := unmarshalResolvedPath(rpStr)
 				pks := extractResolvedPubkeys(rp)
 				s.indexResolvedPathHops(tx, pks, hopsSeen)
+			} else if relayPM != nil && obsPJ != "" && obsPJ != "[]" {
+				// resolved_path is NULL on live (since #1287 relay data is
+				// persisted as neighbor_edges, not per-observation). Re-resolve
+				// relay-hop attribution from path_json so relay nodes keep their
+				// analytics history across a restart instead of rebuilding only
+				// from post-restart live traffic. relayPM is passed in from
+				// LoadChunked (fetched before any chunk cursor opened).
+				// byNode ONLY — see the Load() counterpart for why the
+				// resolved_path/path-hop indexes must NOT be populated here.
+				// PR #1643 R1 munger #1: unique_prefix-only gate.
+				rp := resolvePathForObsColdLoad(obsPJ, obsIDStr, tx, relayPM, coldLoadAmbiguousHopsSkipped)
+				for _, pk := range extractResolvedPubkeys(rp) {
+					s.addToByNode(tx, pk)
+				}
 			}
 
 			tx.Observations = append(tx.Observations, obs)
diff --git a/cmd/server/load_graph_invariant_test.go b/cmd/server/load_graph_invariant_test.go
new file mode 100644
index 00000000..e128756b
--- /dev/null
+++ b/cmd/server/load_graph_invariant_test.go
@@ -0,0 +1,90 @@
+package main
+
+import (
+	"database/sql"
+	"path/filepath"
+	"testing"
+	"time"
+
+	_ "modernc.org/sqlite"
+)
+
+// TestLoad_PanicsWhenGraphNotLoadedAndEdgesExist pins the startup-ordering
+// invariant (munger R1 #2). Graph-load-before-packet-load is the entire
+// premise of PR #1643's fix: without an in-memory neighbor graph, the
+// path_json relay-hop fallback cannot resolve hops, so relay-node analytics
+// history collapses. main.go currently does the right thing — but nothing
+// asserts the ordering, so a future refactor could silently regress.
+//
+// Load() must panic when neighbor_edges has rows but s.graph.Load() returns
+// nil. Fast-fail at startup beats silently-wrong attribution.
+func TestLoad_PanicsWhenGraphNotLoadedAndEdgesExist(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "test.db")
+
+	rw, err := sql.Open("sqlite", "file:"+dbPath+"?_journal_mode=WAL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rw.Close()
+
+	exec := func(s string, args ...interface{}) {
+		if _, err := rw.Exec(s, args...); err != nil {
+			t.Fatalf("setup exec failed: %v\nSQL: %s", err, s)
+		}
+	}
+
+	// Minimal CoreScope schema. PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE transmissions (
+		id INTEGER PRIMARY KEY,
+		raw_hex TEXT, hash TEXT, first_seen TEXT,
+		route_type INTEGER, payload_type INTEGER, payload_version INTEGER,
+		decoded_json TEXT
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observations (
+		id INTEGER PRIMARY KEY, transmission_id INTEGER,
+		observer_id TEXT, observer_name TEXT,
+		direction TEXT, snr REAL, rssi REAL, score INTEGER,
+		path_json TEXT, timestamp TEXT, raw_hex TEXT, resolved_path TEXT
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observers (rowid INTEGER PRIMARY KEY, id TEXT, name TEXT, iata TEXT)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE nodes (
+		public_key TEXT PRIMARY KEY, name TEXT, role TEXT, lat REAL, lon REAL,
+		last_seen TEXT, first_seen TEXT, advert_count INTEGER DEFAULT 0
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE schema_version (version INTEGER)`)
+	exec(`INSERT INTO schema_version (version) VALUES (1)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE neighbor_edges (
+		node_a TEXT NOT NULL,
+		node_b TEXT NOT NULL,
+		count INTEGER DEFAULT 1,
+		last_seen TEXT,
+		PRIMARY KEY (node_a, node_b)
+	)`)
+	now := time.Now().UTC().Format(time.RFC3339)
+	exec(`INSERT INTO neighbor_edges (node_a, node_b, count, last_seen) VALUES (?, ?, ?, ?)`,
+		"aaa", "bbb", 5, now)
+
+	d, err := OpenDB(dbPath)
+	if err != nil {
+		t.Fatalf("OpenDB: %v", err)
+	}
+	defer d.conn.Close()
+
+	// Deliberately DO NOT call store.graph.Store(...). s.graph.Load() returns
+	// nil → the bug condition the invariant guard must catch.
+	store := NewPacketStore(d, &PacketStoreConfig{RetentionHours: 72})
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Fatalf("Load() must panic when neighbor_edges has rows but graph is nil; got no panic")
+		}
+	}()
+	_ = store.Load()
+}
diff --git a/cmd/server/loadchunk_ambiguous_prefix_test.go b/cmd/server/loadchunk_ambiguous_prefix_test.go
new file mode 100644
index 00000000..9a0d4265
--- /dev/null
+++ b/cmd/server/loadchunk_ambiguous_prefix_test.go
@@ -0,0 +1,172 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"path/filepath"
+	"testing"
+	"time"
+
+	_ "modernc.org/sqlite"
+)
+
+// createTestDBAmbiguousPrefix builds a fixture where TWO repeaters share the
+// same 2-char hop prefix. An observation's path_json carries ONLY the
+// ambiguous prefix (no longer prefix that would disambiguate). With no
+// neighbor_edges seeded, the cold-load fallback in scanAndMergeChunk has
+// nothing to anchor on — yet the current code resolves the prefix anyway
+// (via observation_count_fallback or candidate[0]) and over-attributes the
+// hop to ONE of the two repeaters. That is the time-travel bug munger
+// flagged: the historical packet's actual relay is unknown, but the loader
+// picks today's tier-4 winner against ~7-day-old observations.
+func createTestDBAmbiguousPrefix(t *testing.T, relayA, relayB, hop, firstSeen string) string {
+	t.Helper()
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "test.db")
+
+	conn, err := sql.Open("sqlite", dbPath+"?_journal_mode=WAL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	exec := func(s string, args ...interface{}) {
+		if _, err := conn.Exec(s, args...); err != nil {
+			t.Fatalf("setup exec failed: %v\nSQL: %s", err, s)
+		}
+	}
+
+	// PREFLIGHT: async=true reason="test fixture: in-memory t.TempDir SQLite, never touches a real DB."
+	exec(`CREATE TABLE transmissions (
+		id INTEGER PRIMARY KEY,
+		raw_hex TEXT, hash TEXT, first_seen TEXT,
+		route_type INTEGER, payload_type INTEGER, payload_version INTEGER,
+		decoded_json TEXT
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observations (
+		id INTEGER PRIMARY KEY,
+		transmission_id INTEGER,
+		observer_id TEXT, observer_name TEXT,
+		direction TEXT, snr REAL, rssi REAL, score INTEGER,
+		path_json TEXT, timestamp TEXT,
+		raw_hex TEXT,
+		resolved_path TEXT
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observers (rowid INTEGER PRIMARY KEY, id TEXT, name TEXT, iata TEXT)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE nodes (
+		public_key TEXT PRIMARY KEY, name TEXT, role TEXT, lat REAL, lon REAL,
+		last_seen TEXT, first_seen TEXT, advert_count INTEGER DEFAULT 0
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE schema_version (version INTEGER)`)
+	exec(`INSERT INTO schema_version (version) VALUES (1)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE INDEX idx_tx_first_seen ON transmissions(first_seen)`)
+
+	// Two repeaters sharing the same 2-char prefix `hop`.
+	// Different advert_counts so tier-4 tiebreak deterministically picks one
+	// (proving the bug: it over-attributes to the higher-count node).
+	exec(`INSERT INTO nodes (public_key, name, role, advert_count) VALUES (?,?,?,?)`,
+		relayA, "Relay A", "repeater", 50)
+	exec(`INSERT INTO nodes (public_key, name, role, advert_count) VALUES (?,?,?,?)`,
+		relayB, "Relay B", "repeater", 10)
+
+	// Aged 48h so it lands in the background window (loadChunk path).
+	exec("INSERT INTO transmissions VALUES (?,?,?,?,0,4,1,?)",
+		1, "aa", "hashamb_1", firstSeen, `{}`)
+	exec("INSERT INTO observations (id, transmission_id, observer_id, observer_name, direction, snr, rssi, score, path_json, timestamp, raw_hex, resolved_path) VALUES (?,?,?,?,?,?,?,?,?,?,?,NULL)",
+		1, 1, "obs1", "Obs1", "RX", -10.0, -80.0, 5, fmt.Sprintf(`[%q]`, hop), firstSeen, "")
+
+	return dbPath
+}
+
+// TestLoadChunk_AmbiguousPrefix_SkipsAttribution pins the fix for the
+// time-travel attribution gate (munger R1 #1). When path_json carries an
+// ambiguous prefix that matches multiple repeaters, the cold-load path
+// MUST NOT pick a winner via affinity/observation-count tiebreak — today's
+// affinity winner is not necessarily the historical hop. Safer to
+// under-attribute (skip byNode for that hop) than to mis-attribute.
+func TestLoadChunk_AmbiguousPrefix_SkipsAttribution(t *testing.T) {
+	relayA := "aabbccddeeff00112233445566778899aabbccddeeff00112233445566778899"
+	relayB := "aa1122334455667788990011223344556677889900112233445566778899aabb"
+	hop := "aa" // 2-char prefix shared by both relayA and relayB
+
+	aged := time.Now().UTC().Add(-48 * time.Hour).Format(time.RFC3339)
+	dbPath := createTestDBAmbiguousPrefix(t, relayA, relayB, hop, aged)
+
+	db, err := OpenDB(dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.conn.Close()
+
+	store := NewPacketStore(db, &PacketStoreConfig{
+		RetentionHours:  72,
+		HotStartupHours: 1, // hot load skips the 48h-old row → goes to loadChunk
+	})
+	// Empty graph: no neighbor-affinity tiebreak signal. Mirrors a freshly
+	// restarted server whose only relay info is the prefix map.
+	store.graph.Store(NewNeighborGraph())
+
+	if err := store.LoadChunked(0); err != nil {
+		t.Fatalf("LoadChunked: %v", err)
+	}
+	if got := len(store.byNode[relayA]) + len(store.byNode[relayB]); got != 0 {
+		t.Fatalf("setup: hot load unexpectedly picked up 48h-old row "+
+			"(byNode total=%d, want 0) — test would not exercise loadChunk", got)
+	}
+
+	chunkStart := time.Now().UTC().Add(-72 * time.Hour)
+	chunkEnd := time.Now().UTC().Add(-1 * time.Hour)
+	if err := store.loadChunk(chunkStart, chunkEnd); err != nil {
+		t.Fatalf("loadChunk: %v", err)
+	}
+
+	// Neither repeater may be over-attributed. The hop is ambiguous → the
+	// cold-load loader MUST NOT pick one as the byNode owner.
+	if got := len(store.byNode[relayA]); got != 0 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 0 — ambiguous-prefix hop "+
+			"was over-attributed to relayA (time-travel attribution bug)", relayA, got)
+	}
+	if got := len(store.byNode[relayB]); got != 0 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 0 — ambiguous-prefix hop "+
+			"was over-attributed to relayB (time-travel attribution bug)", relayB, got)
+	}
+}
+
+// TestLoad_AmbiguousPrefix_SkipsAttribution covers the hot-window Load()
+// path. Same setup as the loadChunk test but the row falls inside the hot
+// window so it is loaded by Load() / scanAndMergeChunk.
+func TestLoad_AmbiguousPrefix_SkipsAttribution(t *testing.T) {
+	relayA := "bbccddeeff00112233445566778899aabbccddeeff00112233445566778899aa"
+	relayB := "bb112233445566778899001122334455667788990011223344556677889900aa"
+	hop := "bb"
+
+	ts := time.Now().UTC().Format(time.RFC3339)
+	dbPath := createTestDBAmbiguousPrefix(t, relayA, relayB, hop, ts)
+
+	db, err := OpenDB(dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.conn.Close()
+
+	store := NewPacketStore(db, &PacketStoreConfig{RetentionHours: 72})
+	store.graph.Store(NewNeighborGraph())
+
+	if err := store.LoadChunked(0); err != nil {
+		t.Fatalf("LoadChunked: %v", err)
+	}
+
+	if got := len(store.byNode[relayA]); got != 0 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 0 — ambiguous-prefix hop "+
+			"was over-attributed (hot Load path)", relayA, got)
+	}
+	if got := len(store.byNode[relayB]); got != 0 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 0 — ambiguous-prefix hop "+
+			"was over-attributed (hot Load path)", relayB, got)
+	}
+}
diff --git a/cmd/server/loadchunk_pathjson_fallback_test.go b/cmd/server/loadchunk_pathjson_fallback_test.go
new file mode 100644
index 00000000..518fe161
--- /dev/null
+++ b/cmd/server/loadchunk_pathjson_fallback_test.go
@@ -0,0 +1,180 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"path/filepath"
+	"testing"
+	"time"
+
+	_ "modernc.org/sqlite"
+)
+
+// createTestDBPathJSONNoResolvedPath builds a fixture that mirrors the LIVE
+// deployment state after #1287: observations carry a path_json hop list but
+// observations.resolved_path is NULL (the ingestor no longer writes it; relay
+// data is persisted as aggregate neighbor_edges instead). A single repeater
+// node whose public_key starts with hopPrefix lets the in-memory prefix map
+// resolve that hop unambiguously to relayPubkey.
+//
+// The transmission's decoded_json is empty ({}), so relayPubkey is NOT an
+// endpoint (pubKey/destPubKey/srcPubKey). The ONLY way it can enter
+// s.byNode is via path_json → resolvePathForObs relay-hop resolution.
+func createTestDBPathJSONNoResolvedPath(t *testing.T, relayPubkey, hopPrefix, firstSeen string) string {
+	t.Helper()
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "test.db")
+
+	conn, err := sql.Open("sqlite", dbPath+"?_journal_mode=WAL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	exec := func(s string, args ...interface{}) {
+		if _, err := conn.Exec(s, args...); err != nil {
+			t.Fatalf("setup exec failed: %v\nSQL: %s", err, s)
+		}
+	}
+
+	// PREFLIGHT: async=true reason="test fixture: in-memory t.TempDir SQLite, never touches a real DB. Tables are CREATE-from-empty in a one-shot OpenDB call, not a schema migration over existing data."
+	exec(`CREATE TABLE transmissions (
+		id INTEGER PRIMARY KEY,
+		raw_hex TEXT, hash TEXT, first_seen TEXT,
+		route_type INTEGER, payload_type INTEGER, payload_version INTEGER,
+		decoded_json TEXT
+	)`)
+	// resolved_path column present (matches live schema) but left NULL.
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observations (
+		id INTEGER PRIMARY KEY,
+		transmission_id INTEGER,
+		observer_id TEXT, observer_name TEXT,
+		direction TEXT, snr REAL, rssi REAL, score INTEGER,
+		path_json TEXT, timestamp TEXT,
+		raw_hex TEXT,
+		resolved_path TEXT
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE observers (rowid INTEGER PRIMARY KEY, id TEXT, name TEXT, iata TEXT)`)
+	// Production nodes schema uses public_key (not pubkey) — getAllNodes /
+	// buildPrefixMap reads public_key, role, advert_count, first_seen.
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE nodes (
+		public_key TEXT PRIMARY KEY, name TEXT, role TEXT, lat REAL, lon REAL,
+		last_seen TEXT, first_seen TEXT, advert_count INTEGER DEFAULT 0
+	)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE TABLE schema_version (version INTEGER)`)
+	exec(`INSERT INTO schema_version (version) VALUES (1)`)
+	// PREFLIGHT: async=true reason="test fixture, in-memory tmpdir DB"
+	exec(`CREATE INDEX idx_tx_first_seen ON transmissions(first_seen)`)
+
+	// Repeater node so canAppearInPath() admits it to the prefix map.
+	exec(`INSERT INTO nodes (public_key, name, role, advert_count) VALUES (?,?,?,?)`,
+		relayPubkey, "Relay One", "repeater", 10)
+
+	exec("INSERT INTO transmissions VALUES (?,?,?,?,0,4,1,?)",
+		1, "aa", "hashpjf_1", firstSeen, `{}`)
+	// resolved_path explicitly NULL; path_json carries the relay hop prefix.
+	exec("INSERT INTO observations (id, transmission_id, observer_id, observer_name, direction, snr, rssi, score, path_json, timestamp, raw_hex, resolved_path) VALUES (?,?,?,?,?,?,?,?,?,?,?,NULL)",
+		1, 1, "obs1", "Obs1", "RX", -10.0, -80.0, 5, fmt.Sprintf(`[%q]`, hopPrefix), firstSeen, "")
+
+	return dbPath
+}
+
+// TestLoadChunked_ResolvesRelayHopsFromPathJSON_WhenResolvedPathEmpty pins the
+// fix for the "relay-node analytics empty after every restart" bug.
+//
+// On live, observations.resolved_path is 100% NULL (since #1287 the ingestor
+// persists relay data as neighbor_edges, not per-observation resolved_path).
+// The cold-load paths (Load / scanAndMergeChunk) indexed relay hops ONLY from
+// resolved_path, so a relay node's path-hop attribution was never rebuilt on
+// startup — it only re-accumulated from live traffic, collapsing the activity
+// timeline to "just the hour the server restarted".
+//
+// The fix: when resolved_path is empty, fall back to resolving the hops from
+// the persisted path_json using the in-memory prefix map + neighbor graph
+// (exactly what the live ingest path already does), then index the relay hops.
+func TestLoadChunked_ResolvesRelayHopsFromPathJSON_WhenResolvedPathEmpty(t *testing.T) {
+	relayPK := "aabbccddeeff00112233445566778899aabbccddeeff00112233445566778899"
+	hop := "aa" // 2-hex-char path hop; unique 2-char prefix of relayPK
+
+	ts := time.Now().UTC().Format(time.RFC3339)
+	dbPath := createTestDBPathJSONNoResolvedPath(t, relayPK, hop, ts)
+
+	db, err := OpenDB(dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.conn.Close()
+
+	if !db.hasResolvedPath {
+		t.Fatalf("setup: fixture should expose resolved_path column; hasResolvedPath=false")
+	}
+
+	store := NewPacketStore(db, &PacketStoreConfig{RetentionHours: 72})
+	// Empty graph is sufficient: a single prefix candidate resolves without
+	// neighbor-affinity disambiguation. Mirrors a freshly restarted server
+	// that has loaded its neighbor_edges snapshot before the packet load.
+	store.graph.Store(NewNeighborGraph())
+
+	if err := store.LoadChunked(0); err != nil {
+		t.Fatalf("LoadChunked: %v", err)
+	}
+
+	// The relay pubkey only reachable through path_json resolution must be
+	// indexed in byNode for the transmission.
+	if got := len(store.byNode[relayPK]); got != 1 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 1 — cold load did not "+
+			"resolve relay hops from path_json when resolved_path was NULL "+
+			"(relay history lost on restart)", relayPK, got)
+	}
+}
+
+// TestLoadChunk_ResolvesRelayHopsFromPathJSON_WhenResolvedPathEmpty covers the
+// background-window loader (loadBackgroundChunks → loadChunk), which on live
+// loads everything older than hotStartupHours (24h) up to retentionHours
+// (168h). Without the path_json fallback here, a relay node's analytics for
+// the older 6 days would still vanish on every restart even with the hot
+// window fixed.
+func TestLoadChunk_ResolvesRelayHopsFromPathJSON_WhenResolvedPathEmpty(t *testing.T) {
+	relayPK := "ccddeeff00112233445566778899aabbccddeeff00112233445566778899aabb"
+	hop := "cc"
+
+	// Aged 48h so it falls in the background window, not the hot window.
+	aged := time.Now().UTC().Add(-48 * time.Hour).Format(time.RFC3339)
+	dbPath := createTestDBPathJSONNoResolvedPath(t, relayPK, hop, aged)
+
+	db, err := OpenDB(dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.conn.Close()
+
+	store := NewPacketStore(db, &PacketStoreConfig{
+		RetentionHours:  72,
+		HotStartupHours: 1, // hot load must NOT pick up the 48h-old row
+	})
+	store.graph.Store(NewNeighborGraph())
+
+	if err := store.LoadChunked(0); err != nil {
+		t.Fatalf("LoadChunked: %v", err)
+	}
+	if got := len(store.byNode[relayPK]); got != 0 {
+		t.Fatalf("setup: hot load unexpectedly picked up 48h-old row; "+
+			"byNode[relayPK]=%d (want 0) — test would not exercise loadChunk", got)
+	}
+
+	chunkStart := time.Now().UTC().Add(-72 * time.Hour)
+	chunkEnd := time.Now().UTC().Add(-1 * time.Hour)
+	if err := store.loadChunk(chunkStart, chunkEnd); err != nil {
+		t.Fatalf("loadChunk: %v", err)
+	}
+
+	if got := len(store.byNode[relayPK]); got != 1 {
+		t.Errorf("byNode[%s]: got %d transmissions, want 1 — background loadChunk "+
+			"did not resolve relay hops from path_json when resolved_path was NULL "+
+			"(relay history lost on restart for the older retention window)", relayPK, got)
+	}
+}
diff --git a/cmd/server/main.go b/cmd/server/main.go
index 7491157c..c541dca7 100644
--- a/cmd/server/main.go
+++ b/cmd/server/main.go
@@ -198,6 +198,23 @@ func main() {
 	// In-memory packet store
 	store := NewPacketStore(database, cfg.PacketStore, cfg.CacheTTL)
 	store.config = cfg
+
+	// Load the persisted neighbor graph BEFORE the packet load so the
+	// chunked loader can resolve relay-hop pubkeys from path_json. Since
+	// #1287 the ingestor persists relay data only as aggregate
+	// neighbor_edges — observations.resolved_path is never written — so
+	// without an available graph at load time a relay node's analytics
+	// history would rebuild only from post-restart live traffic (the
+	// "timeline empty after every restart" bug). neighbor_edges is small,
+	// so this adds negligible latency before the HTTP listener binds. The
+	// fresh-DB branch (no snapshot) still builds in-memory AFTER the load
+	// below, because BuildFromStore needs the loaded packets.
+	neighborEdgesPersisted := neighborEdgesTableExists(database.conn)
+	if neighborEdgesPersisted {
+		store.graph.Store(loadNeighborEdgesFromDB(database.conn))
+		log.Printf("[neighbor] loaded persisted neighbor graph")
+	}
+
 	// #1009: chunked Load with early HTTP readiness. LoadChunked runs
 	// asynchronously and signals FirstChunkReady after the first chunk
 	// is merged so the HTTP listener can bind without waiting for the
@@ -228,9 +245,9 @@ func main() {
 		go store.loadBackgroundChunks()
 	}
 
-	// Initialize persisted neighbor graph.
-	// Per #1287, schema migrations all live in the ingestor (see
-	// dbschema.Apply). The server merely loads the snapshot here and
+	// Neighbor graph: the persisted snapshot (if present) was already
+	// loaded above, before the packet load. Per #1287 schema migrations
+	// all live in the ingestor; the server only reads the snapshot and
 	// then refreshes it via the recompNeighborGraph slot every 60s.
 	dbPath = database.path
 	database.hasResolvedPath = true // dbschema.AssertReady above already verified observations.resolved_path exists
@@ -238,11 +255,7 @@ func main() {
 	// WaitGroup for background init steps that gate /api/healthz readiness.
 	var initWg sync.WaitGroup
 
-	// Load or build neighbor graph
-	if neighborEdgesTableExists(database.conn) {
-		store.graph.Store(loadNeighborEdgesFromDB(database.conn))
-		log.Printf("[neighbor] loaded persisted neighbor graph")
-	} else {
+	if !neighborEdgesPersisted {
 		// No persisted snapshot yet (e.g. fresh DB before the ingestor
 		// has run its first edge-build cycle). Build an in-memory graph
 		// from the packets we already have so reads aren't empty. We
diff --git a/cmd/server/neighbor_persist.go b/cmd/server/neighbor_persist.go
index 54a40cc8..98d24818 100644
--- a/cmd/server/neighbor_persist.go
+++ b/cmd/server/neighbor_persist.go
@@ -131,6 +131,63 @@ func resolvePathForObs(pathJSON, observerID string, tx *StoreTx, pm *prefixMap,
 	return resolved
 }
 
+// resolvePathForObsColdLoad is the cold-load (Load / loadChunk / scanAndMergeChunk)
+// variant of resolvePathForObs that gates hop resolution on `unique_prefix`
+// only. Live ingest uses the affinity/observation-count tiebreak via
+// resolvePathForObs because it has roughly-current state. Cold load runs
+// against observations up to retentionHours (168h) old, where today's
+// affinity winner ≠ historical affinity winner for that prefix — silently
+// mis-attributing the relay (PR #1643 R1 munger #1, "time-travel attribution
+// gate").
+//
+// Behavior: hops whose prefix maps to exactly one repeater resolve as
+// usual; hops whose prefix maps to multiple candidates return nil and
+// increment skipped (caller-owned counter for observability — a single
+// summary log line at the end of Load surfaces the total).
+//
+// Under-attribute > mis-attribute (reviewer consensus on PR #1643).
+func resolvePathForObsColdLoad(pathJSON, observerID string, tx *StoreTx, pm *prefixMap, skipped *int) []*string {
+	hops := parsePathJSON(pathJSON)
+	if len(hops) == 0 {
+		return nil
+	}
+	resolved := make([]*string, len(hops))
+	for i, hop := range hops {
+		// unique_prefix iff the prefix maps to exactly one candidate
+		// after the observer-known nonRelay filter. Mirrors the
+		// `len(candidates) == 1 → "unique_prefix"` arm of
+		// resolveWithContext (store.go ~6380). Calling resolveWithContext
+		// with a nil graph and empty context skips the affinity/
+		// observation-count tiers entirely — but tier-4
+		// observation_count_fallback would still pick a winner for
+		// ambiguous prefixes, which is exactly what we must NOT do.
+		// Hence the explicit candidate-count check here.
+		h := strings.ToLower(hop)
+		candidates := pm.m[h]
+		if len(pm.nonRelay) > 0 && len(candidates) > 0 {
+			filtered := candidates[:0:0]
+			for j := range candidates {
+				if _, isListener := pm.nonRelay[strings.ToLower(candidates[j].PublicKey)]; isListener {
+					continue
+				}
+				filtered = append(filtered, candidates[j])
+			}
+			candidates = filtered
+		}
+		if len(candidates) == 1 {
+			pk := strings.ToLower(candidates[0].PublicKey)
+			resolved[i] = &pk
+			continue
+		}
+		// Ambiguous (len > 1) or no_match (len == 0). Under-attribute.
+		if len(candidates) > 1 && skipped != nil {
+			*skipped++
+		}
+		// resolved[i] stays nil; extractResolvedPubkeys filters it out.
+	}
+	return resolved
+}
+
 // marshalResolvedPath converts []*string to JSON for in-memory caching.
 func marshalResolvedPath(rp []*string) string {
 	if len(rp) == 0 {
diff --git a/cmd/server/store.go b/cmd/server/store.go
index 7b9e4677..5fab20f9 100644
--- a/cmd/server/store.go
+++ b/cmd/server/store.go
@@ -649,6 +649,18 @@ func (s *PacketStore) Load() error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
+	// Startup-ordering invariant (PR #1643 R1 munger #2). Graph-load-
+	// before-packet-load is the entire premise of the relay-history
+	// cold-load fix: without an in-memory neighbor graph, the path_json
+	// fallback below cannot disambiguate relay hops, so relay-node
+	// analytics history silently collapses on every restart. main.go
+	// loads neighbor_edges → s.graph BEFORE invoking Load/LoadChunked;
+	// fast-fail here so a future refactor that swaps that ordering trips
+	// the panic at startup instead of regressing the bug silently.
+	if neighborEdgesTableExists(s.db.conn) && s.graph.Load() == nil {
+		panic("packet store Load(): neighbor_edges table has rows but s.graph is nil — graph must be loaded before packet load (see main.go #1643 invariant)")
+	}
+
 	t0 := time.Now()
 
 	// Count total transmissions for logging.
@@ -728,6 +740,19 @@ func (s *PacketStore) Load() error {
 			ORDER BY t.first_seen ASC, o.timestamp DESC`
 	}
 
+	// Relay-hop fallback inputs. When resolved_path is empty (always, on
+	// live, since #1287 the ingestor persists relay data as neighbor_edges
+	// instead) we re-resolve relay hops from path_json using the prefix
+	// map. PR #1643 R1 munger #1: cold load resolves ONLY when the prefix
+	// is unique (no affinity tiebreak against ≤168h-old observations,
+	// which would silently mis-attribute hops). Fetched BEFORE opening
+	// the rows cursor below: getCachedNodesAndPM issues its own DB query,
+	// which would deadlock against the still-open cursor on a single-
+	// connection SQLite pool. Load holds s.mu.Lock(), so calling
+	// getCachedNodesAndPM directly is safe.
+	_, relayPM := s.getCachedNodesAndPM()
+	var coldLoadAmbiguousHopsSkipped int
+
 	rows, err := s.db.conn.Query(loadSQL)
 	if err != nil {
 		return err
@@ -825,6 +850,21 @@ func (s *PacketStore) Load() error {
 				pks := extractResolvedPubkeys(rp)
 				// Single point of truth — see indexResolvedPathHops doc + #1558.
 				s.indexResolvedPathHops(tx, pks, hopsSeen)
+			} else if relayPM != nil && obsPJ != "" && obsPJ != "[]" {
+				// resolved_path not persisted — reconstruct relay hops from
+				// path_json so relay-node analytics history survives a restart.
+				// Index into byNode ONLY: the resolved_path / path-hop indexes
+				// (indexResolvedPathHops) are cross-checked by handleNodePaths
+				// against the persisted resolved_path column, which is NULL
+				// here — populating them would make that SQL confirmation fail
+				// and wrongly drop the tx from paths-through (#1352). byNode is
+				// what the node-analytics activity timeline reads.
+				// PR #1643 R1 munger #1: gate on unique_prefix only — ambiguous
+				// hops are silently dropped (skipped counter logged at end).
+				rp := resolvePathForObsColdLoad(obsPJ, obsIDStr, tx, relayPM, &coldLoadAmbiguousHopsSkipped)
+				for _, pk := range extractResolvedPubkeys(rp) {
+					s.addToByNode(tx, pk)
+				}
 			}
 
 			tx.Observations = append(tx.Observations, obs)
@@ -900,6 +940,10 @@ func (s *PacketStore) Load() error {
 			len(s.packets), s.totalObs, elapsed, s.trackedMemoryMB(), s.estimatedMemoryMB())
 	}
 	s.loadMultibyteCapFromDB()
+	if coldLoadAmbiguousHopsSkipped > 0 {
+		log.Printf("[store] cold load: skipped %d ambiguous-prefix relay hops (unique_prefix gate, PR #1643 R1)",
+			coldLoadAmbiguousHopsSkipped)
+	}
 	// Kick off background subpath + path-hop index builds (#1008).
 	// The goroutine acquires s.mu.Lock() and so will block until Load's
 	// deferred Unlock fires when this function returns. HTTP handlers
@@ -919,6 +963,28 @@ func (s *PacketStore) Load() error {
 // byPayloadType is updated here incrementally. byPathHop, spIndex, and
 // distHops are NOT updated here — the caller (loadBackgroundChunks) rebuilds
 // those once after all chunks are merged.
+
+// accumulateDedup appends pks to byTx[txID], deduplicating per-tx via the
+// parallel seenByTx set. Used by loadChunk to build the per-tx relay-hop
+// pubkey unions outside the merge critical section.
+func accumulateDedup(byTx map[int][]string, seenByTx map[int]map[string]bool, txID int, pks []string) {
+	if len(pks) == 0 {
+		return
+	}
+	seen := seenByTx[txID]
+	if seen == nil {
+		seen = make(map[string]bool, len(pks))
+		seenByTx[txID] = seen
+	}
+	for _, pk := range pks {
+		if seen[pk] {
+			continue
+		}
+		seen[pk] = true
+		byTx[txID] = append(byTx[txID], pk)
+	}
+}
+
 func (s *PacketStore) loadChunk(from, to time.Time) error {
 	fromStr := from.UTC().Format(time.RFC3339)
 	toStr := to.UTC().Format(time.RFC3339)
@@ -955,6 +1021,22 @@ func (s *PacketStore) loadChunk(from, to time.Time) error {
 			ORDER BY t.first_seen ASC, o.timestamp DESC`
 	}
 
+	// Relay-hop fallback inputs. observations.resolved_path is NULL on
+	// every live deployment (since #1287 the ingestor persists relay data
+	// as aggregate neighbor_edges, not per-observation resolved_path), so
+	// for this background-loaded older window we re-resolve relay hops
+	// from the persisted path_json using the prefix map. PR #1643 R1
+	// munger #1: cold load resolves ONLY when the prefix is unique
+	// (affinity-tier resolution against ≤168h-old observations would
+	// silently mis-attribute hops). Fetched BEFORE opening the rows
+	// cursor below: getCachedNodesAndPM issues its own DB query, which
+	// would deadlock against the open cursor on a single-connection SQLite
+	// pool.
+	s.mu.RLock()
+	_, relayPM := s.getCachedNodesAndPM()
+	s.mu.RUnlock()
+	var coldLoadAmbiguousHopsSkipped int
+
 	rows, err := s.db.conn.Query(chunkSQL, fromStr, toStr)
 	if err != nil {
 		return err
@@ -973,6 +1055,11 @@ func (s *PacketStore) loadChunk(from, to time.Time) error {
 	// the rest of loadChunk's "build local, merge under lock" shape.
 	localResolvedPKsByTx := make(map[int][]string)
 	localResolvedSeenByTx := make(map[int]map[string]bool)
+	// Path_json fallback pubkeys (resolved_path NULL): indexed into byNode
+	// ONLY at merge, kept separate from localResolvedPKsByTx because they must
+	// NOT enter the resolved_path/path-hop indexes (see the per-row comment).
+	localByNodePKsByTx := make(map[int][]string)
+	localByNodeSeenByTx := make(map[int]map[string]bool)
 	var localTotalObs int
 	var localTrackedBytes int64
 	var localMaxTxID int
@@ -1083,20 +1170,20 @@ func (s *PacketStore) loadChunk(from, to time.Time) error {
 			if rpStr != "" {
 				rp := unmarshalResolvedPath(rpStr)
 				pks := extractResolvedPubkeys(rp)
-				if len(pks) > 0 {
-					seen := localResolvedSeenByTx[txID]
-					if seen == nil {
-						seen = make(map[string]bool, len(pks))
-						localResolvedSeenByTx[txID] = seen
-					}
-					for _, pk := range pks {
-						if seen[pk] {
-							continue
-						}
-						seen[pk] = true
-						localResolvedPKsByTx[txID] = append(localResolvedPKsByTx[txID], pk)
-					}
-				}
+				accumulateDedup(localResolvedPKsByTx, localResolvedSeenByTx, txID, pks)
+			} else if relayPM != nil && obsPJ != "" && obsPJ != "[]" {
+				// resolved_path not persisted — reconstruct relay hops from
+				// path_json so the older retention window keeps relay-node
+				// history across a restart (mirrors the hot-window fix in
+				// scanAndMergeChunk and the live ingest path). These go into a
+				// SEPARATE accumulator indexed into byNode ONLY at merge — they
+				// must not enter the resolved_path/path-hop indexes, which
+				// handleNodePaths cross-checks against the NULL resolved_path
+				// column (#1352).
+				// PR #1643 R1 munger #1: unique_prefix-only gate.
+				rp := resolvePathForObsColdLoad(obsPJ, obsIDStr, tx, relayPM, &coldLoadAmbiguousHopsSkipped)
+				pks := extractResolvedPubkeys(rp)
+				accumulateDedup(localByNodePKsByTx, localByNodeSeenByTx, txID, pks)
 			}
 		}
 	}
@@ -1207,6 +1294,12 @@ func (s *PacketStore) loadChunk(from, to time.Time) error {
 			if pks := localResolvedPKsByTx[tx.ID]; len(pks) > 0 {
 				s.indexResolvedPathHops(tx, pks, hopsSeen)
 			}
+			// path_json fallback (resolved_path NULL): byNode ONLY, so relay
+			// nodes keep their analytics history across a restart without
+			// polluting the resolved_path/path-hop indexes (#1352).
+			for _, pk := range localByNodePKsByTx[tx.ID] {
+				s.addToByNode(tx, pk)
+			}
 		}
 		s.mu.Unlock()
 		runtime.Gosched()
@@ -1229,6 +1322,10 @@ func (s *PacketStore) loadChunk(from, to time.Time) error {
 	s.mu.Unlock()
 
 	log.Printf("[store] background chunk [%s, %s) merged: %d tx, %d obs", fromStr, toStr, len(localPackets), localTotalObs)
+	if coldLoadAmbiguousHopsSkipped > 0 {
+		log.Printf("[store] background chunk: skipped %d ambiguous-prefix relay hops (unique_prefix gate, PR #1643 R1)",
+			coldLoadAmbiguousHopsSkipped)
+	}
 	return nil
 }