Blackwater Behemoth from Eternal Palace is absolutely bugged.
Sometimes, it phases from the first plataform to the next barely 20 seconds after the start of the encounter.
In other occasions, it stays in the first plataform and never phases, never goes to the second plataform.
And if the raid wipes, if a player releases as soon as possible, the game disconnects.
Seriously, Blizzard needs to fix this boss as soon as possible. It is impossible to defeat Mythic Behemoth this way.