shift/hand glitch

When i hold shift my arm glitches and instead of being like this ( \ ) it goes like this ( / ). The slash represents player's arm.

What I expected to happen was for my hand to stay "unbroken".

What actually happened was my hand went from this ( \ ), to this ( / ). The slash represents player's arm

Steps to Reproduce:
1. hold shift (or whatever your crouch key is...)
2. (for me at least) hand "breaks"