Midgardsormr Animation Bug (Keeper of the Lake)

Date & Time: 12:30PM ST (10/2/2018)
Frequency: Always
World name: Faerie
Character name: Aristotle Avinroo
Monster name: Midgardsormr
Area and coordinates: Final boss of Keeper of the Lake
Steps:
1. Begin combat with Midgardsormr.

When Midgardsormr is not attacking, his body will remain far away from the arena. When he does attack, it will snap back to where it should be. When the attack animation finishes, it pulls back again. Originally, his head and neck stayed in the same place during combat. Since his position doesn't change and combat is otherwise unaffected, I assume this is an animation bug.

Below are two videos to compare:

My video:
https://youtu.be/be_eWQWkkTM

Video of combat from 2015:
https://youtu.be/7hfvhykTAfo?t=117