Hi !
I encountered several bugs on this boss, making it quite difficult to kill :
1/ Animation wise, I don't know if it's because I'm on very low settings, but it can be really difficult to predict its moves, and sometimes it hits while not facing you, or just totally randomly (probably server lag/problems with the following)
2/ The boss seems to have problems reacting well to Aether Jump and/or Light-bringer, notably when his shield is up. He tries to push you aside (sometimes it does, sometimes it doesn't) and it can result to the following : if he's next to a ledge, you just fall from the ledge down to the core and get TP back to town, while his Health Bar is still up top your HUD, or you can clipped down the arena and can cast spell while running, running at insane speed.

All in all I think the TP mechanic is quite glitched on this boss and he could use a little love :)