fix: refresh the retained on-air scene

src/MBN_STOCK_WEBVIEW.Playout/Interop/DynamicK3dSession.cs

@@ -550,18 +550,33 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
         var engine = _engine!;
         var player = _player!;
         var outputChannel = _outputChannel;
-        object? playingScene = null;
+        // Tornado2 can return an incomplete GetPlayingScene proxy. The scene loaded,
+        // prepared, and promoted by Play is the only trusted reference for an in-place
+        // refresh, and it remains retained until the normal take-out/unload lifecycle.
+        if (_preparedScene is not null)
+        {
+            throw new InvalidOperationException(
+                "An on-air update cannot run while another scene is prepared.");
+        }
+
+        var currentScene = ReusableScene(_currentScene, cue.SceneName)
+            ?? throw new InvalidOperationException(
+                "No matching retained on-air scene is available.");
+        if (SupportsLifecycleCallbacks && _pendingPlayCallbacks != 0)
+        {
+            throw new InvalidOperationException(
+                "An on-air update cannot run while scene playback is pending.");
+        }
+
         var transactionStarted = false;
 
         try
         {
-            playingScene = InvokeRequired(player, "GetPlayingScene", layoutIndex);
-
             foreach (var mutation in cue.Mutations ?? [])
             {
                 if (IsBeforeTransactionSceneSetupMutation(mutation))
                 {
-                    ApplySceneSetupMutation(playingScene, mutation);
+                    ApplySceneSetupMutation(currentScene.Value, mutation);
                 }
             }
 
@@ -570,7 +585,7 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
 
             foreach (var field in cue.Fields ?? [])
             {
-                ApplyField(playingScene, field);
+                ApplyField(currentScene.Value, field);
             }
 
             foreach (var mutation in cue.Mutations ?? [])
@@ -580,11 +595,11 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
                 // explicit in-transaction ordering.
                 if (!IsBeforeTransactionSceneSetupMutation(mutation))
                 {
-                    ApplyTransactionMutation(playingScene, mutation);
+                    ApplyTransactionMutation(currentScene.Value, mutation);
                 }
             }
 
-            Invoke(playingScene, "QueryVariables");
+            Invoke(currentScene.Value, "QueryVariables");
             if (outputChannel.HasValue)
             {
                 Invoke(engine, "EndTransactionOnChannel", outputChannel.GetValueOrDefault());
@@ -595,20 +610,8 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
             }
 
             transactionStarted = false;
-            Invoke(player, "Prepare", layoutIndex, playingScene);
+            Invoke(player, "Prepare", layoutIndex, currentScene.Value);
             InvokeTrackedPlay(layoutIndex);
-
-            // GetPlayingScene can return the same RCW or another RCW for the same COM
-            // scene. An in-place page update must never retire/unload the active scene.
-            if (_currentScene is null)
-            {
-                _currentScene = new SceneReference(playingScene, cue.SceneName);
-                playingScene = null;
-            }
-            else if (ReferenceEquals(_currentScene.Value, playingScene))
-            {
-                playingScene = null;
-            }
         }
         catch
         {
@@ -626,10 +629,6 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
 
             throw;
         }
-        finally
-        {
-            ReleaseComObject(playingScene);
-        }
     }
 
     public void TakeOut(int layoutIndex, PlayoutTakeOutScope scope)