immortal Esh?

Happened a few times now: in the Esh/Tul fight, occasionally the bosses become permanently phased and they simply don't move on to the next stage of the fight. Seems to happen primarily when Esh is slightly above half hp.

Even logging out doesn't fix it. The fight bricks and becomes impossible. I've actually tried sitting there for 10 minutes to see if it eventually would move on and it did not.