When walking / running in Minecraft and moving the mouse a little, the cursor at some point does some oversteering where the character is suddenly looking in a whole different direction than the mouse movement would suggest it.
Steps to reproduce:
Standard keyboard-configuration, standard mouse configuration
Walk / run in Minecraft and move the cursor from 45° left to 45° right of the normal FOV
It seems like Minecraft re-sets the mouse position at some point. An output of the coordinates of the mouse cursor confirms this.
This bug only happens in 1.14 Minecraft.
Related issues
Comments


I experimented a little bit. It seems like this error only shows when the window has a specific size. The one you get after dragging the window to the upper edge of the screen for resizing, for example. Commented this on your post, too. Maybe could help understand that error.
I also have this bug, but it has already been reported here: https://bugs.mojang.com/browse/MC-144107.
If you are running MC in a window have you tried playing fullscreen, because that solved this issue for me?