diff --git a/socketserver/server/handlecore.go b/socketserver/server/handlecore.go
index 46c8adfd..2871159f 100644
--- a/socketserver/server/handlecore.go
+++ b/socketserver/server/handlecore.go
@@ -204,7 +204,7 @@ var CloseRebalance = websocket.CloseError{Code: websocket.CloseGoingAway, Text:
 var CloseGotBinaryMessage = websocket.CloseError{Code: websocket.CloseUnsupportedData, Text: "got binary packet"}
 
 // CloseTimedOut is the termination reason when the client fails to send or respond to ping frames.
-var CloseTimedOut = websocket.CloseError{Code: websocket.CloseNoStatusReceived, Text: "no ping replies for 5 minutes"}
+var CloseTimedOut = websocket.CloseError{Code: 3003, Text: "no ping replies for 5 minutes"}
 
 // CloseTooManyBufferedMessages is the termination reason when the sending thread buffers too many messages.
 var CloseTooManyBufferedMessages = websocket.CloseError{Code: websocket.CloseMessageTooBig, Text: "too many pending messages"}
@@ -216,7 +216,7 @@ var CloseFirstMessageNotHello = websocket.CloseError{
 }
 
 var CloseNonUTF8Data = websocket.CloseError{
-	Code: 4001,
+	Code: websocket.CloseUnsupportedData,
 	Text: "Non UTF8 data recieved. Network corruption likely.",
 }
 
diff --git a/socketserver/server/publisher.go b/socketserver/server/publisher.go
index 4ec4dbf3..cad5b62a 100644
--- a/socketserver/server/publisher.go
+++ b/socketserver/server/publisher.go
@@ -96,13 +96,17 @@ func DumpBacklogData() {
 // This will only send data for CacheTypePersistent and CacheTypeLastOnly because those do not involve timestamps.
 func SendBacklogForNewClient(client *ClientInfo) {
 	client.Mutex.Lock() // reading CurrentChannels
+	curChannels := make([]string, len(client.CurrentChannels))
+	copy(curChannels, client.CurrentChannels)
+	client.Mutex.Unlock()
+
 	PersistentLSMLock.RLock()
 	for _, cmd := range GetCommandsOfType(PushCommandCacheInfo{CacheTypePersistent, MsgTargetTypeChat}) {
 		chanMap := CachedLastMessages[cmd]
 		if chanMap == nil {
 			continue
 		}
-		for _, channel := range client.CurrentChannels {
+		for _, channel := range curChannels {
 			msg, ok := chanMap[channel]
 			if ok {
 				msg := ClientMessage{MessageID: -1, Command: cmd, origArguments: msg.Data}
@@ -119,7 +123,7 @@ func SendBacklogForNewClient(client *ClientInfo) {
 		if chanMap == nil {
 			continue
 		}
-		for _, channel := range client.CurrentChannels {
+		for _, channel := range curChannels {
 			msg, ok := chanMap[channel]
 			if ok {
 				msg := ClientMessage{MessageID: -1, Command: cmd, origArguments: msg.Data}
@@ -129,7 +133,6 @@ func SendBacklogForNewClient(client *ClientInfo) {
 		}
 	}
 	CachedLSMLock.RUnlock()
-	client.Mutex.Unlock()
 }
 
 // insertionSort implements insertion sort.