Bug playable behavior scene loading async only working in a build not editor play

where the loading is done with this

Spoiler: loading script

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Playables;
3. using UnityEngine.SceneManagement;
4.  
5. public class TimelineSceneLoadAsync : PlayableAsset
6. {
7.     public SceneReference sceneName;
8.     public AsyncDataPipe asyncDataPipe;
9.  
10.     public override Playable CreatePlayable(PlayableGraph graph, GameObject owner)
11.     {
12.         var playable = ScriptPlayable<TimelineSceneLoadAsyncBehaviour>.Create(graph);
13.         var sceneLoadBehaviour = playable.GetBehaviour();
14.         sceneLoadBehaviour.sceneName = sceneName;
15.         sceneLoadBehaviour.asyncDataPipe = asyncDataPipe;
16.         return playable;
17.     }
18. }
19. public class TimelineSceneLoadAsyncBehaviour : PlayableBehaviour
20. {
21.     public string sceneName = "";
22.     public AsyncDataPipe asyncDataPipe;
23.  
24.     public override void OnBehaviourPlay(Playable playable, FrameData info)
25.     {
26.         if (asyncDataPipe.async == null)
27.             asyncDataPipe.async= SceneManager.LoadSceneAsync(sceneName, LoadSceneMode.Additive);
28.         asyncDataPipe.async.allowSceneActivation = false;
29.     }
30. }

and scene activation is done with that

Spoiler: scene activation

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Playables;
3.  
4. public class TimelineSceneActivate : PlayableAsset
5. {
6.     public AsyncDataPipe asyncDataPipe;
7.  
8.     public override Playable CreatePlayable(PlayableGraph graph, GameObject owner)
9.     {
10.         var playable = ScriptPlayable<TimelineSceneActivateBehaviour>.Create(graph);
11.         var sceneActivateBehaviour = playable.GetBehaviour();
12.         sceneActivateBehaviour.asyncDataPipe = asyncDataPipe;
13.         return playable;
14.     }
15. }
16. public class TimelineSceneActivateBehaviour : PlayableBehaviour
17. {
18.     public AsyncDataPipe asyncDataPipe;
19.  
20.     public override void OnBehaviourPlay(Playable playable, FrameData info)
21.     {
22.         if (asyncDataPipe.async != null)
23.             asyncDataPipe.async.allowSceneActivation = true;
24.     }
25. }

using a data pipe (aka channel) SO to store the async operation
both loading and activation are on the same playable track like so


in a build it works fine and by the time activation is reached (the second block) the async load has finished
but in editor this never loads the scene