Game stay in processes after quit

Hi Epic!

Our testers found a bug. Game stay in processes after exit.
We attached to game process and found a thread which infinitely waiting the end of GPU work with samples.
Here the code:

// Some samples still need the GPU to get done. Use async task to get this done...
TFunction<void()> FlushTask = [LastObjects{ MoveTemp(Objects) }]()
{
	while (1)
	{
		int32 Idx = 0;
		for (; Idx < LastObjects.Num(); ++Idx)
		{
			if (LastObjects[Idx].GPUFence.IsValid() && !LastObjects[Idx].GPUFence->Poll())
			{
				break;
			}
		}
		if (Idx == LastObjects.Num())
		{
			break;
		}

		FPlatformProcess::Sleep(5.0f / 1000.0f);
	}
};
Async(EAsyncExecution::ThreadPool, MoveTemp(FlushTask));

In this code the the “LastObjects[Idx].GPUFence->Poll()” always return false. And as result of infinity loop the main thread infinitely wait and can’t exit from app.

Thanks!