🐛 Trying to fix sync API of messages

DysonNetwork.Sphere/Chat/ChatService.cs

@@ -470,6 +470,7 @@ public partial class ChatService(
             .ToListAsync();
 
         var changesMembers = changes
+            .Where(c => c.Message != null)
             .Select(c => c.Message!.Sender)
             .DistinctBy(x => x.Id)
             .ToList();