What I expected to happen
Mobs should be moving around normally, and performing their default actions.

What actually happened
Instead, They keep jumping and spinning around themselves in the same place. Some monsters, like zombies and slimes won't try to chase and attack you. Spiders and tamed wolves will try to attack while jumping, spinning, moving slowly and randomly towards the target.

Steps to Reproduce
1. Find a place with some mobs
2. Observe their behavior.