Locked inside boss arena after killing map boss

Bug Report ID: #3357678580

After I killed the boss on a T15 map, a barrier and door locked me inside the arena. I could not click the door to get out to the rest of the map and since I had not cleared the map of the rest of rare mobs I am unable to complete it, bricking my waystone :((

It happened again on another map:
Bug Report ID: #3012444221