diff --git a/pkg/rtc/mediatrack.go b/pkg/rtc/mediatrack.go
index c7ca7e30d..20617079f 100644
--- a/pkg/rtc/mediatrack.go
+++ b/pkg/rtc/mediatrack.go
@@ -7,6 +7,7 @@ import (
 	"github.com/pion/rtcp"
 	"github.com/pion/webrtc/v3"
 	"go.uber.org/atomic"
+	"google.golang.org/protobuf/proto"
 
 	"github.com/livekit/protocol/livekit"
 	"github.com/livekit/protocol/logger"
@@ -96,15 +97,17 @@ func (t *MediaTrack) SdpCid() string {
 }
 
 func (t *MediaTrack) ToProto() *livekit.TrackInfo {
-	info := t.MediaTrackReceiver.TrackInfo()
+	info := proto.Clone(t.MediaTrackReceiver.TrackInfo()).(*livekit.TrackInfo)
 	info.Muted = t.IsMuted()
 	info.Simulcast = t.IsSimulcast()
 	layers := t.MediaTrackReceiver.GetVideoLayers()
+	t.lock.RLock()
 	for _, layer := range layers {
 		if int(layer.Quality) < len(t.layerSSRCs) {
 			layer.Ssrc = t.layerSSRCs[layer.Quality]
 		}
 	}
+	t.lock.RUnlock()
 	info.Layers = layers
 
 	return info
@@ -135,8 +138,11 @@ func (t *MediaTrack) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.Tra
 		}
 	})
 
+	isNew := false
 	t.lock.Lock()
 	if t.Receiver() == nil {
+		isNew = true
+
 		wr := sfu.NewWebRTCReceiver(
 			receiver,
 			track,
@@ -165,12 +171,6 @@ func (t *MediaTrack) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.Tra
 		wr.OnStatsUpdate(func(_ *sfu.WebRTCReceiver, stat *livekit.AnalyticsStat) {
 			t.params.Telemetry.TrackStats(livekit.StreamType_UPSTREAM, t.PublisherID(), t.ID(), stat)
 		})
-		t.params.Telemetry.TrackPublished(
-			context.Background(),
-			t.PublisherID(),
-			t.PublisherIdentity(),
-			t.ToProto(),
-		)
 
 		t.buffer = buff
 
@@ -188,15 +188,29 @@ func (t *MediaTrack) AddReceiver(receiver *webrtc.RTPReceiver, track *webrtc.Tra
 
 	if t.IsSimulcast() {
 		layer := sfu.RidToLayer(track.RID())
+		t.lock.Lock()
 		if int(layer) < len(t.layerSSRCs) {
 			t.layerSSRCs[layer] = uint32(track.SSRC())
 		}
+		t.lock.Unlock()
+	}
+
+	if isNew {
+		t.params.Telemetry.TrackPublished(
+			context.Background(),
+			t.PublisherID(),
+			t.PublisherIdentity(),
+			t.ToProto(),
+		)
 	}
 
 	buff.Bind(receiver.GetParameters(), track.Codec().RTPCodecCapability)
 }
 
 func (t *MediaTrack) TrySetSimulcastSSRC(layer uint8, ssrc uint32) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
 	if int(layer) < len(t.layerSSRCs) && t.layerSSRCs[layer] == 0 {
 		t.layerSSRCs[layer] = ssrc
 	}
diff --git a/pkg/rtc/mediatrackreceiver.go b/pkg/rtc/mediatrackreceiver.go
index a80cedc75..a1cb074de 100644
--- a/pkg/rtc/mediatrackreceiver.go
+++ b/pkg/rtc/mediatrackreceiver.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/pion/rtcp"
 	"go.uber.org/atomic"
+	"google.golang.org/protobuf/proto"
 
 	"github.com/livekit/protocol/livekit"
 	"github.com/livekit/protocol/logger"
@@ -31,7 +32,7 @@ type MediaTrackReceiver struct {
 
 	lock            sync.RWMutex
 	receiver        sfu.TrackReceiver
-	layerDimensions sync.Map // livekit.VideoQuality => *livekit.VideoLayer
+	layerDimensions map[livekit.VideoQuality]*livekit.VideoLayer
 
 	// track audio fraction lost
 	downFracLostLock   sync.Mutex
@@ -60,7 +61,8 @@ type MediaTrackReceiverParams struct {
 
 func NewMediaTrackReceiver(params MediaTrackReceiverParams) *MediaTrackReceiver {
 	t := &MediaTrackReceiver{
-		params: params,
+		params:          params,
+		layerDimensions: make(map[livekit.VideoQuality]*livekit.VideoLayer),
 	}
 
 	t.MediaTrackSubscriptions = NewMediaTrackSubscriptions(MediaTrackSubscriptionsParams{
@@ -234,9 +236,11 @@ func (t *MediaTrackReceiver) TrackInfo() *livekit.TrackInfo {
 }
 
 func (t *MediaTrackReceiver) UpdateVideoLayers(layers []*livekit.VideoLayer) {
+	t.lock.Lock()
 	for _, layer := range layers {
-		t.layerDimensions.Store(layer.Quality, layer)
+		t.layerDimensions[layer.Quality] = layer
 	}
+	t.lock.Unlock()
 
 	t.MediaTrackSubscriptions.UpdateVideoLayers()
 	if t.onVideoLayerUpdate != nil {
@@ -248,12 +252,11 @@ func (t *MediaTrackReceiver) UpdateVideoLayers(layers []*livekit.VideoLayer) {
 
 func (t *MediaTrackReceiver) GetVideoLayers() []*livekit.VideoLayer {
 	layers := make([]*livekit.VideoLayer, 0)
-	t.layerDimensions.Range(func(q, val interface{}) bool {
-		if layer, ok := val.(*livekit.VideoLayer); ok {
-			layers = append(layers, layer)
-		}
-		return true
-	})
+	t.lock.RLock()
+	for _, layer := range t.layerDimensions {
+		layers = append(layers, proto.Clone(layer).(*livekit.VideoLayer))
+	}
+	t.lock.RUnlock()
 
 	return layers
 }
@@ -276,12 +279,11 @@ func (t *MediaTrackReceiver) GetQualityForDimension(width, height uint32) liveki
 	// default sizes representing qualities low - high
 	layerSizes := []uint32{180, 360, origSize}
 	var providedSizes []uint32
-	t.layerDimensions.Range(func(_, val interface{}) bool {
-		if layer, ok := val.(*livekit.VideoLayer); ok {
-			providedSizes = append(providedSizes, layer.Height)
-		}
-		return true
-	})
+	t.lock.RLock()
+	for _, layer := range t.layerDimensions {
+		providedSizes = append(providedSizes, layer.Height)
+	}
+	t.lock.RUnlock()
 	if len(providedSizes) > 0 {
 		layerSizes = providedSizes
 		// comparing height always
diff --git a/pkg/rtc/room.go b/pkg/rtc/room.go
index 1bace48ef..982a79d26 100644
--- a/pkg/rtc/room.go
+++ b/pkg/rtc/room.go
@@ -865,9 +865,10 @@ func (r *Room) audioUpdateWorker() {
 		// changedSpeakers need to include previous speakers that are no longer speaking
 		for sid, speaker := range lastActiveMap {
 			if nextActiveMap[sid] == nil {
-				speaker.Level = 0
-				speaker.Active = false
-				changedSpeakers = append(changedSpeakers, speaker)
+				inactiveSpeaker := proto.Clone(speaker).(*livekit.SpeakerInfo)
+				inactiveSpeaker.Level = 0
+				inactiveSpeaker.Active = false
+				changedSpeakers = append(changedSpeakers, inactiveSpeaker)
 			}
 		}
 
diff --git a/pkg/sfu/downtrackspreader.go b/pkg/sfu/downtrackspreader.go
index f7f1e828e..3d0e2a5f9 100644
--- a/pkg/sfu/downtrackspreader.go
+++ b/pkg/sfu/downtrackspreader.go
@@ -103,10 +103,10 @@ func (d *DownTrackSpreader) HasDownTrack(peerID livekit.ParticipantID) bool {
 func (d *DownTrackSpreader) Broadcast(layer int32, pkt *buffer.ExtPacket) {
 	d.downTrackMu.RLock()
 	downTracks := d.downTracks
-	free := d.free
+	numFree := len(d.free)
 	d.downTrackMu.RUnlock()
 
-	if d.params.Threshold == 0 || len(downTracks)-len(free) < d.params.Threshold {
+	if d.params.Threshold == 0 || (len(downTracks)-numFree) < d.params.Threshold {
 		// serial - not enough down tracks for parallelization to outweigh overhead
 		for _, dt := range downTracks {
 			if dt != nil {
diff --git a/pkg/sfu/streamtrackermanager.go b/pkg/sfu/streamtrackermanager.go
index 0a54fb339..604d9a26d 100644
--- a/pkg/sfu/streamtrackermanager.go
+++ b/pkg/sfu/streamtrackermanager.go
@@ -116,7 +116,12 @@ func (s *StreamTrackerManager) AddTracker(layer int32) *StreamTracker {
 					break
 				}
 			}
-			if !exempt || layer > s.maxExpectedLayer {
+
+			s.lock.RLock()
+			maxExpectedLayer := s.maxExpectedLayer
+			s.lock.RUnlock()
+
+			if !exempt || layer > maxExpectedLayer {
 				s.removeAvailableLayer(layer)
 			} else {
 				s.logger.Debugw("not removing exempt layer", "layer", layer)
@@ -294,7 +299,9 @@ func (s *StreamTrackerManager) addAvailableLayer(layer int32) {
 
 	s.availableLayers = append(s.availableLayers, layer)
 	sort.Slice(s.availableLayers, func(i, j int) bool { return s.availableLayers[i] < s.availableLayers[j] })
-	layers := s.availableLayers
+
+	var layers []int32
+	layers = append(layers, s.availableLayers...)
 	s.lock.Unlock()
 
 	s.logger.Debugw("available layers changed - layer seen", "added", layer, "layers", layers)