After spinning the camera really quickly left or right, you are not able to move (WASD) and your targeting (block highlighting, etc.) is locked to being directly underneath you.

Steps to reproduce:

1. You need some way to lock your mouse to a corner of the screen. One way to do this, which I used, is to connect a drawing pad and hold the pen on the pad such that it keeps the mouse locked in one place.
2. Let the camera in Minecraft spin for about 10-20 seconds. With a drawing tablet, you may need to constantly move your pen slightly so the mouse pointer's position is consistently updated.
3. Afterwards, you should not be able to move, and your targeting is stuck to being directly underneath your position.

This bug appears to be client-sided, since the server still knows the correct rotation. This can be shown using the command /tp ^ ^ ^5 to teleport 5 blocks in the direction you're facing.