A wild guess, bug given the introduction of the flaps code base merged with the release “by error”, and most likely the deadline for DX12 implementation is 3 months from now (after it will be internal testing and validation for Xbox), there is a possibility some of the refactoring done for DX12 is creeping in the DX11 code base right now and causes this. Because handling CPU/GPU fences/sync is really different when dealing with DX12 command buffers, which in turn makes the code using different buffer handling/logic and synchronization points, which in turn causes disruption in the flow for DX11. Just a wild guess, but the visible deterioration of CPU/GPU sync problems I can monitor and see tells me there are more profound changes to the rendering engine beneath.