Sneaking can get stuck

Normally, sneaking does not allow you to get to the very edge of a block. If you do get to the very edge, you can't even move.

How to reproduce

1. Stand on a block with an edge to your right
2. Sneak right as far as possible
3. Try to sneak forward and backward ( you can)
4. Now jump and move ever so slightly further right without falling off
5. Now try to sneak forward and backward ( you can't)