Lich Fight Crashes

OVERVIEW
Two lich fights in a row now I've been crashing consistently and it makes them impossible to finish since the timer in on and ticking even when you're not logged in.

WHAT HAPPENS
In the fights, normally when the phase is changing, the game client becomes unresponsive. Eventually, I get kicked and it says an unexpected disconnection has occurred.

TECHNICALITIES
I am aware there are two different liches, but I did not take note of the name of the liches these happened on. Both fights were seemingly the same which massive amounts of green particle effects. I'm sorry I can't be more helpful with the description.