Sneak Bug?

Put the summary of the bug you're having here

What I expected to happen was...:
Usually when I sneak it's smooth.

What actually happened was...:
When I sneak it's not so smooth... I don't really know how to explain it. It's just not the same as 1.7.10 or any other version. It just seemed a little weird to me.

Steps to Reproduce:
1. Go on singleplayer/multiplayed
2. Sneak