Sneak button

Hello,

In minecraft 1.11.2+ (pre-release included) there is a bug/glitch where if you press shift (sneak button) once and release it the player will stay sneaked, but when i press another button that interacts within the game it will stop sneak mode.
I have footage of the bug from the versions mentioned here:
1.11.2
1.12pre-release6
1.12pre-release7
It also appears to be flying down when flying in creative.
If i missed something please point it out to get better quality bug reports in the near future.

Kind regards,
QHpix