I encountered this problem after updating the game from 1.14.60 to 1.16.0.

When I am standing still and move my mouse to look around, everything works just fine.

However, if I keep flying in one direction to force new chunks to be loaded and moving my mouse at the same time, there is a significant lag in changing of field of view as compared to the actual movement of my mouse. (i.e. The actual rotation of my field of view is far less than my expectation)

I feel that this problem is extremely unfriendly to pvp players, because they need to aim and change FOV frequently for hitting their targets. This is also quite disturbing for all other players because it causes the control to be less smooth and quite uncomfortable.

I believe this problem is not associated with chunk generation. I tested separately on a new world, a pre-generated world and on a multiplayer server, and found that this problem happens every time. I also tested on my android device and found that the touch screen was working fine. As a result, I assume that this problem is caused by change in handling of threads responsible for rendering new loaded chunks and threads responsible for processing mouse input signal.

I am not sure whether this problem is a device-specific problem or not, because I found no similar reports of this problem. If this is a common problem, I look forward for an optimization.

Thank you very much!

The video below is a demonstration of the problem. I am not sure whether it is clear enough or not but I hope it helps.

UPDATE: I asked some other windows 10 bedrock players and found that they also had the same problem. Hence this should not be a device-specific problem but a general problem.(one of them plays with a quite good computer with an RTX2070 card)