The bug

I was messing around with the setblock command when I noticed this. If you are standing in an air block, and it is changed to a solid block, you cannot sneak. If you were sneaking, and try to stop, the camera placement doesn't change, even though the player model does if you have third person view. 

How to reproduce

1. Stand or sneak in a space surrounded by blocks
2. Use the setblock command on the block you are standing in
3. If you were sneaking, and let go, the camera placement won't change. If you were standing, you won't be able to sneak.