diff --git a/lib/src/realtime_mixin.dart b/lib/src/realtime_mixin.dart
index 389acea8..c230b978 100644
--- a/lib/src/realtime_mixin.dart
+++ b/lib/src/realtime_mixin.dart
@@ -1,14 +1,16 @@
 import 'dart:async';
 import 'dart:convert';
+
 import 'package:flutter/foundation.dart';
-import 'package:web_socket_channel/web_socket_channel.dart';
 import 'package:web_socket_channel/status.dart' as status;
-import 'exception.dart';
-import 'realtime_subscription.dart';
+import 'package:web_socket_channel/web_socket_channel.dart';
+
 import 'client.dart';
+import 'exception.dart';
 import 'realtime_message.dart';
 import 'realtime_response.dart';
 import 'realtime_response_connected.dart';
+import 'realtime_subscription.dart';
 
 typedef WebSocketFactory = Future<WebSocketChannel> Function(Uri uri);
 typedef GetFallbackCookie = String? Function();
@@ -87,10 +89,14 @@ mixin RealtimeMixin {
             break;
         }
       }, onDone: () {
-        final subscriptions = List.from(_subscriptions.values);
-        for (var subscription in subscriptions) {
-          subscription.close();
+        if (!_notifyDone || _creatingSocket) return;
+        // create a copy of the keys to avoid concurrent modification
+        var subscriptionKeys = _subscriptions.keys.toList();
+        for (var key in subscriptionKeys) {
+          // close the subscription
+          _subscriptions[key]?.close();
         }
+
         _channels.clear();
         _closeConnection();
       }, onError: (err, stack) {
@@ -157,13 +163,23 @@ mixin RealtimeMixin {
   }
 
   void _cleanup(List<String> channels) {
+    // create a list of channels to remove from the list of channels
+    List<String> channelsToRemove = [];
+
     for (var channel in channels) {
+      // check if the channel is still in use
       bool found = _subscriptions.values
           .any((subscription) => subscription.channels.contains(channel));
+
       if (!found) {
-        _channels.remove(channel);
+        // if not, add it to the list of channels to remove
+        channelsToRemove.add(channel);
       }
     }
+
+    for (var channel in channelsToRemove) {
+      _channels.remove(channel);
+    }
   }
 
   void handleError(RealtimeResponse response) {