So I was working on solo flawless of Spire of the Watcher and earlier today during damage phase for Akelous, the first boss, after he did his knockback explosion signaling the end of the damage phase, instead of resetting the nodes, he instead just stayed in the middle of the arena being vulnerable for damage. After 5 minutes of just ability spamming and dumping all my ammo into him, he finally died without ever ending his damage phase, even giving me time to go collect ammo. I know I definitely didn't do enough damage to trigger his extended DPS phase, so I have no clue how to replicate it.