Keep custom battle open during lobby updates (#8790)

src/main/csharp/net/eagle0/clients/unity/eagle0/Assets/ConnectionHandler/ConnectionHandler.cs

@@ -780,12 +780,12 @@ public class ConnectionHandler : MonoBehaviour, ILobbySubscriber, IDisposable {
         fetchedNewGameLeaders.AddRange(lobbyResponse.NewGameOptions.AvailableLeaders);
 
         MainQueue.Q.Enqueue(() => {
-            // Skip lobby UI updates if we've already left the connection UI.
-            // The lobby response may arrive after the game has started (e.g., when creating a new
-            // game), and the connection canvas is inactive, causing GetComponentInParent to fail.
-            // This check must be inside the queue callback since the state may change between
-            // when the response arrives and when this callback executes.
-            if (!IsConnectionModeActive()) return;
+            // Skip lobby UI updates if we've already left the connection UI or opened the custom
+            // battle panel. A lobby response may already be in flight when either transition
+            // happens, so it must not switch the visible panel back to the lobby.
+            // This check must be inside the queue callback since the state may change between when
+            // the response arrives and when this callback executes.
+            if (!IsConnectionModeActive() || customBattlePanel.gameObject.activeSelf) return;
 
             ResourceFetcher.headshotFetcher.Prefetch(
                     fetchedNewGameLeaders.Select(a => a.ImagePath));