when screen resolution is set to default (1920x1080) mouse tracking is fine,

but when you change your resolution down to 1280x720, and switch from windowed mode to fullscreen mode (after your world has loaded)

step to recreate
1 .. start minecraft in windowed mode
2 .. select world, wait for it to load and display on screen
3 .. switch to fullscreen, then press escape,try to select any buttons
4 .. get back to game, and move mouse a little, you will see its drifting