Custom Mob Addon DONT MOVE THERE ANIMATION!!!

When i spawn a custom addon mob made by them it did not move it animation instead it walk weird and walk like it in water or something if you dont believe me then try it.

How To Reproduce

STEP 1: Get a Custom Addon in 1.8.

STEP 2: Play In Any World.

STEP 3: Spawn The Custom Addon You Install And Let It Walk And There You Go.

Can you please fix it in a next update thank you

Dont Believe Me Then Click On A Picture To See A GIF Of What Is The Bug Look Like

My Device Is A Galaxy Tab A, SM-T550

This Is For Every Addon That Caused This Bug