The respawn timers are not livelike. Umbral Warriors spawn way to fast after they have been killed. It's not possible to do a Prince Raid with the current situation.
Issue Timeline
3 Aug 2018 svartson created this issue
4 Aug 2018 Uthred triaged this issue
4 Aug 2018 Uthred changed the status of this issue from new to open
4 Aug 2018 Galahad assigned this issue from Nobody to Galahad
4 Aug 2018 Galahad changed the status of this issue from in_progress to resolved
Not sure if this is still relevant but I was down by Prince the other day 11/9 (small man group) and noticed the respawn timer was still pretty quick for the mobs leading up to him. Granted we were only 4 but we're killing 2 reds while the last 2 are already popping on us mid fight. Just seems v fast.