During my last key this boss bugged heavily for us, idk if its related, but i was playing Trickster Subtlety Rogue, when i got exiled, the add that you need to kill to free the Kyrian and get back to the boss would bug out, go out of bounds (ignoring me and trying to move towards the boss platform), and essentially become unkillable due to “Evade” then shortly after disappear altogether, leaving me stuck down at the platform, when i ended up dying due to this, my body also didnt teleport back, making brez impossible.
After a second attempt where it happened again to me, and the key dead cause of it, i decided to swap my spec to Assassination to see if Sub was somehow the cause, but during the third attempt the boss bugged even worse, as soon as we pull the boss casted Exile, which isnt normal, and we also noticed he was casting Exile far more often than normal, often causing overlaps with people getting send down when the previous person is barely killing the add and getting out.
We wiped again due to lack of dmg caused by this, and after forcing a reset, we attempted again where the boss finally started working normally, allowing us to kill it.
Like previously stated, idk if Subtlety was somehow the cause of this, but it single handedly killed a key we couldve timed.
To clarify not once did i use Vanish during the fight, which idk if it even causes issues to begin with.