Bug Report ID: #1 553 485 601 - Hive Colony boss stuck in the first phase

I was doing a Hive Colony, and the fight got stuck on the first It That Was Esh phase, where the boss became invulnerable after dealing enough damage to change the phase and It That Was Tul won't come down from the balcony to progress the fight.

I tested if portaling out, closing the game, or dying to the boss would fix it, but no luck.