I feel like there should be a way to find out what task we’re waiting on but I have no clue how given the information I (and you) obtained from the debugger.
Yes main thread is waiting. Other threads are running. I wouldn’t say none of our gameplay code causes this, but its probably not our fault. While we have full access to source, UE4 still sometimes feels like a black box and behaves mysterious in response to things we do that maybe Epic doesn’t do in QA or in their projects or doesn’t expect.