Mobs walking sideways and backwards

Put the summary of the bug you're having here

What I expected to happen was...:
Mobs would walk normally.

What actually happened was...:
Mobs are walking sideways and backwards.

Steps to Reproduce:
1. Play Minecraft normally...
2. Find a passive, hostile, or neutral mob.
3. Watch them walk. (Best to use a passive mob like a mooshroom or pig and lure them.)