FScene::UpdateSkyCaptureScene - Infinite wait on dx12


I found an issue on XboxOne but I think it is directly related to DirectX 12 so I put this report here. Note that I could not try on Windows because I don’t have Windows 10 on my current system, but when I use DirectX 11, it seems the problem is gone (“seems” because the issue is little random so…).

Well : at the end of the loading, when the BeginPlay is started, the FScene::UpdateSkyCaptureScene is called. It enqueues a series of commands, and waits between them.
When the command starts being executed on the Render thread, a fence is created, the task starts and waits indefinitely for the task to end. Most of the times, it works, but sometimes it doesn’t.

I though it was a deadlock issue at the beginning but it is not, it’s just the Render thread that is locked and waited by others threads. Here is the states of my threads :

I firstly think it was related to the use of loading screen (because the first issue I saw was the GameThread and SlateLoadingThread blocked), but it is just a consequence of the Render thread waiting, not doing the final SlateDrawPass, not stopping the SlateLoadingThread (that the GameThread is waiting).

I am not really an expert of Dx12 so tell me how I can provide you with more information, or what should I check to find the issue.
Is there some dx12 debug tools that can tell me what task is done exactly with which parameters and if these last ones are valid or not.

Here is a sequence diagram of what happens in my game, but the main issue to resolve is still this FScene::UpdateSkyCaptureContents infinite task :

Thank for any help you could bring to me.