diff --git a/.github/workflows/run-unit-tests.yml b/.github/workflows/run-unit-tests.yml
index 5719cc775..eaf4c69f8 100644
--- a/.github/workflows/run-unit-tests.yml
+++ b/.github/workflows/run-unit-tests.yml
@@ -783,6 +783,7 @@ jobs:
           python3 -B test/test_rtttl_rollover.py -v
           python3 -B test/test_rtttl_rollover_recipes.py -v
           python3 -B test/test_companion_ui_deadlines.py -v
+          python3 -B test/test_sensor_ui_polling.py -v
           python3 -B test/test_home_sensor_refresh.py -v
           python3 -B test/test_scrolling_status_bar_rollover.py -v
           python3 -B test/test_gps_voice_buttons.py -v
diff --git a/examples/simple_sensor/UITask.cpp b/examples/simple_sensor/UITask.cpp
index 971f42bd1..2e633f5ea 100644
--- a/examples/simple_sensor/UITask.cpp
+++ b/examples/simple_sensor/UITask.cpp
@@ -100,6 +100,11 @@ void UITask::begin(NodePrefs* node_prefs, const char* build_date, const char* fi
   // v1.2.3 (1 Jan 2025)
   snprintf(_version_info, sizeof(_version_info), "%s (%s)", version, build_date);
   free(version);
+
+  // Make the first read/frame immediately due, including begin() after wrap.
+  const uint32_t now = millis();
+  _last_read = now - 200u;
+  _last_refresh = now - 1000u;
 }
 
 void UITask::resetRadioProfileDisplayPage() {
@@ -208,7 +213,7 @@ void UITask::loop() {
   const bool morse_timing = mesh::morseTimingActive(activeSensorMesh().getProfileRadio());
   if (_display->servicePower(board.isExternalPowered() || board.isUsbHostConnected())) {
     resetRadioProfileDisplayPage();
-    _next_refresh = 0;
+    _last_refresh = millis() - 1000u;
   }
 #if defined(PIN_USER_BTN) && defined(DISPLAY_CLASS) \
     && defined(MOMENTARY_BUTTON_WAKE_FROM_SLEEP) \
@@ -218,12 +223,12 @@ void UITask::loop() {
     if (!_display->isOn()) {
       _display->wake(mesh::ui::DisplayWake::Button);
       resetRadioProfileDisplayPage();
-      _next_refresh = 0;
+      _last_refresh = millis() - 1000u;
     }
     _display->wake(mesh::ui::DisplayWake::Button);
   }
 #elif defined(PIN_USER_BTN)
-  if (millis() >= _next_read) {
+  if (static_cast<uint32_t>(millis() - _last_read) >= 200u) {
     int btnState = digitalRead(PIN_USER_BTN);
     if (btnState != _prevBtnState) {
       if (btnState == USER_BTN_PRESSED) {  // pressed?
@@ -237,17 +242,17 @@ void UITask::loop() {
       }
       _prevBtnState = btnState;
     }
-    _next_read = millis() + 200;  // 5 reads per second
+    _last_read = millis();  // 5 reads per second, timed from completed I/O
   }
 #endif
 
   if (!morse_timing && _display->isOn()) {
-    if (millis() >= _next_refresh) {
+    if (static_cast<uint32_t>(millis() - _last_refresh) >= 1000u) {
       _display->startFrame();
       renderCurrScreen();
       _display->endFrame();
 
-      _next_refresh = millis() + 1000;   // refresh every second
+      _last_refresh = millis();   // refresh every second, after the frame ends
     }
 #if MOMENTARY_BUTTON_WAKE_HOLD_MS > 0 && defined(PIN_USER_BTN)
     if (user_btn.isWakeHoldActive()) _display->wake(mesh::ui::DisplayWake::Button);
diff --git a/examples/simple_sensor/UITask.h b/examples/simple_sensor/UITask.h
index bb909c7e9..b10f3a799 100644
--- a/examples/simple_sensor/UITask.h
+++ b/examples/simple_sensor/UITask.h
@@ -5,7 +5,8 @@
 
 class UITask {
   DisplayDriver* _display;
-  unsigned long _next_read, _next_refresh;
+  // Completion timestamps keep periodic work due across millis() rollover.
+  uint32_t _last_read, _last_refresh;
   int _prevBtnState;
   NodePrefs* _node_prefs;
   char _version_info[32];
@@ -16,7 +17,7 @@ class UITask {
   bool showingSecondaryRadioProfilePage();
   void renderCurrScreen();
 public:
-  UITask(DisplayDriver& display) : _display(&display) { _next_read = _next_refresh = 0; }
+  UITask(DisplayDriver& display) : _display(&display) { _last_read = _last_refresh = 0; }
   void begin(NodePrefs* node_prefs, const char* build_date, const char* firmware_version);
 
   void loop();
diff --git a/test/fixtures/sensor_ui_polling.cpp b/test/fixtures/sensor_ui_polling.cpp
new file mode 100644
index 000000000..6679c624d
--- /dev/null
+++ b/test/fixtures/sensor_ui_polling.cpp
@@ -0,0 +1,247 @@
+// Production header, begin and loop; only hardware/render boundaries are fake.
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+static uint32_t now_ms = 0, read_delay = 0, render_delay = 0, end_delay = 0;
+static unsigned reads = 0, renders = 0;
+static constexpr int HIGH = 1, LOW = 0, USER_BTN_PRESSED = LOW;
+static constexpr int BUTTON_EVENT_NONE = 0;
+static int button_level = HIGH;
+static uint32_t millis() { return now_ms; }
+[[maybe_unused]] static int digitalRead(int pin) {
+  if (pin != 7) std::abort();
+  ++reads;
+  now_ms += read_delay;
+  return button_level;
+}
+struct Radio { bool timing = false; } radio;
+namespace mesh {
+static bool morseTimingActive(const Radio* r) { return r && r->timing; }
+namespace ui { enum class DisplayWake { Button }; }
+}
+struct Board {
+  bool external = false, usb = false;
+  bool isExternalPowered() const { return external; }
+  bool isUsbHostConnected() const { return usb; }
+} board;
+struct SensorMesh {
+  Radio* getProfileRadio() { return &radio; }
+  bool isDualRadioActive() const { return false; }
+} sensor_mesh;
+static SensorMesh& activeSensorMesh() { return sensor_mesh; }
+struct DisplayDriver {
+  bool on = true, changed = false;
+  unsigned frames = 0, wakes = 0;
+  bool servicePower(bool) { bool result = changed; changed = false; return result; }
+  bool isOn() const { return on; }
+  void wake(mesh::ui::DisplayWake) { on = true; ++wakes; }
+  void startFrame() { ++frames; }
+  void endFrame() { now_ms += end_delay; }
+};
+struct MomentaryButton {
+  int event = BUTTON_EVENT_NONE;
+  bool held = false;
+  void begin() { event = BUTTON_EVENT_NONE; }
+  int check() { int result = event; event = BUTTON_EVENT_NONE; return result; }
+  bool isWakeHoldActive() const { return held; }
+} user_btn;
+struct NodePrefs {};
+#include "UITask.h"
+
+@BEGIN@
+@RESET@
+@LOOP@
+void UITask::renderCurrScreen() { ++renders; now_ms += render_delay; }
+
+static const char* scenario;
+static unsigned checks = 0;
+#define CHECK(expr) do { ++checks; if (!(expr)) { \
+  std::fprintf(stderr, "FAIL %s: %s (line %d)\n", scenario, #expr, __LINE__); \
+  return 1; } } while (0)
+
+int main(int argc, char** argv) {
+  if (argc != 2) return 2;
+  scenario = argv[1];
+  DisplayDriver display;
+  NodePrefs prefs;
+  UITask ui(display);
+  now_ms = 10000;
+  if (!std::strcmp(scenario, "zero")) now_ms = 0;
+  else if (!std::strcmp(scenario, "upper-half")) now_ms = 0x80001000u;
+  else if (!std::strcmp(scenario, "max")) now_ms = UINT32_MAX;
+  else if (!std::strcmp(scenario, "wrapped-future")) now_ms = UINT32_MAX - 99u;
+  else if (!std::strcmp(scenario, "zero-boundary")) now_ms = UINT32_MAX - 199u;
+  else if (!std::strcmp(scenario, "overdue-wrap") || !std::strcmp(scenario, "morse-wrap"))
+    now_ms = UINT32_MAX - 1999u;
+  else if (!std::strcmp(scenario, "forced-refresh")) now_ms = 0x80001000u;
+  else if (!std::strcmp(scenario, "forced-zero")
+      || !std::strcmp(scenario, "momentary-zero-wake")
+      || !std::strcmp(scenario, "momentary-zero-morse")) now_ms = UINT32_MAX - 99u;
+  ui.begin(&prefs, "16 Oct 2026", "v1.2.3-test");
+  if (!std::strcmp(scenario, "completion-anchor")) {
+    read_delay = 10;
+    render_delay = 20;
+    end_delay = 30;
+  }
+  ui.loop();
+  CHECK(display.frames == 1 && renders == 1);
+  CHECK(reads == unsigned(TEST_RAW_BUTTON));
+
+  if (!std::strcmp(scenario, "zero") || !std::strcmp(scenario, "upper-half")
+      || !std::strcmp(scenario, "max") || !std::strcmp(scenario, "wrapped-future")) {
+    ++now_ms;
+    ui.loop();
+    CHECK(display.frames == 1 && reads == unsigned(TEST_RAW_BUTTON));
+  } else if (!std::strcmp(scenario, "cadence")) {
+    now_ms += 199;
+    ui.loop();
+    CHECK(reads == unsigned(TEST_RAW_BUTTON) && display.frames == 1);
+    ++now_ms;
+    ui.loop();
+    CHECK(reads == 2u * TEST_RAW_BUTTON && display.frames == 1);
+    now_ms += 799;
+    ui.loop();
+    CHECK(display.frames == 1);
+    ++now_ms;
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "zero-boundary")) {
+    now_ms = UINT32_MAX;
+    ui.loop();
+    CHECK(reads == unsigned(TEST_RAW_BUTTON) && display.frames == 1);
+    now_ms = 0;
+    ui.loop();
+    CHECK(reads == 2u * TEST_RAW_BUTTON && display.frames == 1);
+    now_ms = 799;
+    ui.loop();
+    CHECK(display.frames == 1);
+    ++now_ms;
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "overdue-wrap")) {
+    now_ms = 100;
+    ui.loop();
+    CHECK(display.frames == 2 && reads == 2u * TEST_RAW_BUTTON);
+    ui.loop();
+    CHECK(display.frames == 2 && reads == 2u * TEST_RAW_BUTTON);
+  } else if (!std::strcmp(scenario, "morse-wrap")) {
+    radio.timing = true;
+    now_ms += 1500;
+    ui.loop();
+    CHECK(display.frames == 1 && reads == 2u * TEST_RAW_BUTTON);
+    now_ms += 1000;
+    ui.loop();
+    CHECK(display.frames == 1 && reads == 3u * TEST_RAW_BUTTON);
+    radio.timing = false;
+    ui.loop();
+    CHECK(display.frames == 2 && reads == 3u * TEST_RAW_BUTTON);
+  } else if (!std::strcmp(scenario, "forced-refresh")) {
+    ++now_ms;
+    display.changed = true;
+    ui.loop();
+    CHECK(display.frames == 2);
+    ui.loop();
+    CHECK(display.frames == 2);
+    now_ms = UINT32_MAX;
+    display.changed = true;
+    ui.loop();
+    CHECK(display.frames == 3);
+    now_ms = 0;
+    ui.loop();
+    CHECK(display.frames == 3);
+  } else if (!std::strcmp(scenario, "forced-zero")) {
+    now_ms = 0;
+    display.changed = true;
+    ui.loop();
+    CHECK(display.frames == 2);
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "forced-morse")) {
+    ++now_ms;
+    display.changed = true;
+    radio.timing = true;
+    ui.loop();
+    CHECK(display.frames == 1);
+    ++now_ms;
+    radio.timing = false;
+    ui.loop();
+    CHECK(display.frames == 2);
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "momentary-zero-wake")
+      || !std::strcmp(scenario, "momentary-zero-morse")) {
+    const bool during_morse = !std::strcmp(scenario, "momentary-zero-morse");
+    display.on = false;
+    radio.timing = during_morse;
+    now_ms = 0;
+    user_btn.event = 1;
+    ui.loop();
+#if TEST_MOMENTARY_BUTTON
+    CHECK(display.on && display.wakes == 2);
+    CHECK(display.frames == (during_morse ? 1u : 2u));
+    now_ms = 1;
+    radio.timing = false;
+    ui.loop();
+    CHECK(display.frames == 2);
+    ui.loop();
+    CHECK(display.frames == 2);
+#else
+    CHECK(!display.on && display.frames == 1 && display.wakes == 0);
+#endif
+  } else if (!std::strcmp(scenario, "long-display-off")) {
+    display.on = false;
+    for (unsigned day = 1; day <= 26; ++day) {
+      now_ms = 10000u + day * 86400000u;
+      ui.loop();
+      CHECK(display.frames == 1);
+    }
+    display.on = true; // No force event: elapsed work must remain due.
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "completion-anchor")) {
+    const uint32_t poll_finished = 10000u + (TEST_RAW_BUTTON ? 10u : 0u);
+    const uint32_t frame_finished = poll_finished + 50u;
+    read_delay = render_delay = end_delay = 0;
+    now_ms = poll_finished + 199u;
+    ui.loop();
+    CHECK(reads == unsigned(TEST_RAW_BUTTON) && display.frames == 1);
+    ++now_ms;
+    ui.loop();
+    CHECK(reads == 2u * TEST_RAW_BUTTON && display.frames == 1);
+    now_ms = frame_finished + 999u;
+    ui.loop();
+    CHECK(display.frames == 1);
+    ++now_ms;
+    ui.loop();
+    CHECK(display.frames == 2);
+  } else if (!std::strcmp(scenario, "rebegin")) {
+    ++now_ms;
+    ui.begin(&prefs, "16 Oct 2026", "v1.2.4-test");
+    ui.loop();
+    CHECK(display.frames == 2 && reads == 2u * TEST_RAW_BUTTON);
+  } else if (!std::strcmp(scenario, "button-wake")) {
+    display.on = false;
+    now_ms += 200;
+    button_level = LOW;
+    user_btn.event = 1;
+    ui.loop();
+#if TEST_RAW_BUTTON
+    CHECK(display.on && display.wakes == 2 && reads == 2);
+    // Existing raw-button policy keeps the one-second render throttle.
+    CHECK(display.frames == 1);
+#elif TEST_MOMENTARY_BUTTON
+    CHECK(display.on && display.wakes == 2 && display.frames == 2);
+    user_btn.held = true;
+    ui.loop();
+    CHECK(display.wakes == 3 && display.frames == 2);
+#else
+    CHECK(!display.on && display.wakes == 0 && display.frames == 1);
+#endif
+  } else {
+    std::fprintf(stderr, "unknown scenario: %s\n", scenario);
+    return 2;
+  }
+  std::printf("PASS %s: %u checks\n", scenario, checks);
+}
diff --git a/test/test_morse_loop_policy.py b/test/test_morse_loop_policy.py
index 4d2071695..6503c1e27 100644
--- a/test/test_morse_loop_policy.py
+++ b/test/test_morse_loop_policy.py
@@ -67,6 +67,7 @@ struct UI {
   struct Prefs { const char* node_name="test"; } prefs;
   Prefs* _node_prefs=&prefs;
   uint32_t _next_refresh=0,_alert_expiry=0,ui_started_at=0,next_batt_chck=0;
+  uint32_t _last_refresh=0;
   uint16_t _cached_batt_mv=4000,voltage=3350;
   bool _need_refresh=true;
   char _alert[4]={},_origin[4]={},_msg[4]={};
@@ -224,22 +225,29 @@ int main() {
                 self.assertIn("_display->startFrame()", redraw)
                 code = FIXTURE.replace("@REDRAW@", redraw).replace("@CUTOFF@", "") + r'''
 int main() {
+  constexpr bool sensor_timestamps=@SENSOR_TIMESTAMPS@;
   for(bool external : {false,true}) {
     board.external=external;
     for(unsigned mode=0;mode<4;++mode) {
       UI ui; adc_reads=frames=0;
+      const uint32_t last_refresh_before=ui._last_refresh;
       radio_driver.tx=mode==1; radio_driver.rx=mode==2; radio_driver.cw=mode==3;
       ui.redraw();
       if(mode==1 || mode==2) {
-        assert(frames==0 && adc_reads==0 && ui._next_refresh==0);
+        if(sensor_timestamps)
+          assert(frames==0 && adc_reads==0 && ui._last_refresh==last_refresh_before);
+        else assert(frames==0 && adc_reads==0 && ui._next_refresh==0);
         radio_driver.tx=radio_driver.rx=false;
         ui.redraw(); assert(frames==1 && adc_reads==1);
       } else assert(frames==1 && adc_reads==1);
-      assert(ui._next_refresh>now_ms);
+      if(sensor_timestamps) assert(ui._last_refresh==now_ms);
+      else assert(ui._next_refresh>now_ms);
     }
   }
 }
 '''
+                code = code.replace("@SENSOR_TIMESTAMPS@",
+                                    "true" if path == "examples/simple_sensor/UITask.cpp" else "false")
                 compile_run(self, code, flags=("-Wno-unused-variable",), headers={"Dispatcher.h": RADIO})
 
     def test_actual_full_and_tiny_ui_cutoff_reads_fresh_voltage_even_during_morse(self):
diff --git a/test/test_sensor_ui_polling.py b/test/test_sensor_ui_polling.py
new file mode 100644
index 000000000..a8e3e8b21
--- /dev/null
+++ b/test/test_sensor_ui_polling.py
@@ -0,0 +1,109 @@
+"""Exercise the actual sensor UI header, begin and full loop with a 32-bit clock.
+
+Display, board, radio and button I/O are host adapters. Rendering, physical
+sleep and hardware timing are not qualified by this scheduling regression.
+"""
+from pathlib import Path
+import os
+import shutil
+import subprocess
+import tempfile
+import unittest
+
+from test_replay_reset_integration import extract_braced
+
+ROOT = Path(__file__).resolve().parents[1]
+UI = ROOT / 'examples/simple_sensor'
+FIXTURE = ROOT / 'test/fixtures/sensor_ui_polling.cpp'
+
+
+class SensorUiPollingTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        compiler = os.environ.get('CXX') or shutil.which('g++') or shutil.which('clang++')
+        if not compiler:
+            raise unittest.SkipTest('a host C++17 compiler is required')
+        cls.directory = tempfile.TemporaryDirectory(prefix='sensor-ui-polling-')
+        cls.addClassCleanup(cls.directory.cleanup)
+        work = Path(cls.directory.name)
+        (work / 'helpers/ui').mkdir(parents=True)
+        for stub in ('helpers/ui/DisplayDriver.h', 'helpers/CommonCLI.h'):
+            (work / stub).write_text('#pragma once\n', encoding='ascii')
+        (work / 'UITask.h').write_bytes((UI / 'UITask.h').read_bytes())
+        source = (UI / 'UITask.cpp').read_text(encoding='ascii')
+        generated = FIXTURE.read_text(encoding='ascii')
+        for marker, signature in (
+                ('BEGIN', 'void UITask::begin('),
+                ('RESET', 'void UITask::resetRadioProfileDisplayPage('),
+                ('LOOP', 'void UITask::loop()')):
+            generated = generated.replace('@' + marker + '@', extract_braced(source, signature))
+        cpp = work / 'test.cpp'
+        cpp.write_text(generated, encoding='ascii')
+        sanitize = [] if os.name == 'nt' else [
+            '-fsanitize=address,undefined', '-fno-sanitize-recover=all', '-fno-pie', '-no-pie']
+        cls.binaries = {}
+        for variant in ('none', 'raw', 'momentary'):
+            macros = ['-DTEST_RAW_BUTTON=' + str(int(variant == 'raw')),
+                      '-DTEST_MOMENTARY_BUTTON=' + str(int(variant == 'momentary'))]
+            if variant != 'none':
+                macros += ['-DPIN_USER_BTN=7', '-DDISPLAY_CLASS=DisplayDriver']
+            if variant == 'momentary':
+                macros += ['-DMOMENTARY_BUTTON_WAKE_FROM_SLEEP=1',
+                           '-DMOMENTARY_BUTTON_WAKE_HOLD_MS=1000']
+            binary = work / (variant + ('.exe' if os.name == 'nt' else ''))
+            built = subprocess.run([
+                compiler, '-std=c++17', '-O1', '-g', '-Wall', '-Wextra', '-Werror',
+                *sanitize, *macros, '-I' + str(work), str(cpp), '-o', str(binary)],
+                capture_output=True, text=True, timeout=60)
+            if built.returncode:
+                raise AssertionError(built.stdout + built.stderr)
+            cls.binaries[variant] = binary
+
+    def check_case(self, case):
+        for variant, binary in self.binaries.items():
+            with self.subTest(variant=variant, case=case):
+                checked = subprocess.run([str(binary), case], capture_output=True,
+                                         text=True, timeout=10)
+                self.assertEqual(checked.returncode, 0, checked.stdout + checked.stderr)
+                self.assertIn('PASS ' + case, checked.stdout)
+
+    def test_initial_work_at_zero_upper_half_and_max(self):
+        for case in ('zero', 'upper-half', 'max'):
+            self.check_case(case)
+
+    def test_normal_cadence_and_wrapped_future(self):
+        for case in ('cadence', 'wrapped-future', 'zero-boundary'):
+            self.check_case(case)
+
+    def test_overdue_polling_and_morse_deferral_across_wrap(self):
+        for case in ('overdue-wrap', 'morse-wrap'):
+            self.check_case(case)
+
+    def test_force_and_long_idle_refresh(self):
+        for case in ('forced-refresh', 'long-display-off'):
+            self.check_case(case)
+
+    def test_force_at_zero_and_force_during_morse(self):
+        for case in ('forced-zero', 'forced-morse', 'momentary-zero-wake',
+                     'momentary-zero-morse'):
+            self.check_case(case)
+
+    def test_work_is_anchored_after_io_and_begin_rearms(self):
+        for case in ('completion-anchor', 'rebegin'):
+            self.check_case(case)
+
+    def test_button_wake_paths(self):
+        self.check_case('button-wake')
+
+
+class SensorUiPollingWiringTest(unittest.TestCase):
+    def test_live_role_and_ci_run_the_regression(self):
+        main = (UI / 'main.cpp').read_text(encoding='ascii')
+        self.assertIn('ui_task.begin(', extract_braced(main, 'void setup()'))
+        self.assertIn('ui_task.loop();', extract_braced(main, '\nvoid loop()'))
+        workflow = (ROOT / '.github/workflows/run-unit-tests.yml').read_text(encoding='ascii')
+        self.assertIn('python3 -B test/test_sensor_ui_polling.py -v', workflow)
+
+
+if __name__ == '__main__':
+    unittest.main()