It's a little late, but I just now thought to post this. My friends and I ran the Inverted Spire Nightfall last week and reached the final phase of the boss fight at the bottom of the pit. At one point we all died and were waiting for our respawns, but there were so many enemies wandering around that the game couldn't find a safe place for us to come back. The timer kept running down while we tried to wait it out, but after 2 minutes of waiting we decided to just redo the whole Nightfall. (Note: I took a screenshot that I'll have to add later when I get home from work.)