Video: https://youtu.be/qAZFB5zvpjo
When shifting, you can go back different amounts.
How to reproduce:
step 1: crouch at the end of a block. Check your coordinates.
step 2: move up a bit, then move back, still crouching. Your coordinate is different! :o
I find this kind of strange, but whatever. It just means that players are differently spaced out.
Can you please describe the issue with words and steps to reproduce ?