I don't know of any guilds that even try to attempt to immunity soak P3 after the shadowforce bug was fixed. Not enough space on the platform to do it effectively - shadowforce comes about 30 seconds after Wrath goes out, and assuming you need a few seconds to get in formation both times before stacks are rolling off at their 1/second rate, that means you'll have anywhere from 10-15 stacks still remaining when the first shadowforce comes (and just about gotten rid of them when the felseeker happens).
Main issue, of course, being that you need to fit 4x debuffs into the slowing-shit in the last phase without killing some poor person; considering that even with zero stacks that shit hits for 50K, while a full shadowforce+standing in gaze does about 400K before either is mitigated, that's enough to kill someone. And they've gotta be in there for atleast five ticks :/.
In which case; Backups! That's not bad luck with the chosen targets. That's bad planning :P.
https://www.youtube.com/watch?v=ObFDqwule94
Hunters soaked 5-6 of remaining stacks with deterrence.