What Happened?
In September, some Trial groups and raid leads on PC noticed that they were wiping using the same burn strats that they have used since 2017 in Veteran Halls of Fabrication's Hunter-Killers boss fight. Some seemed to think it was the healers' fault as usual.
However, upon closer inspection of ESOLogs and other information, it seemed that the skill Efficient Purge was not working at all in cleansing the Poison Injections from the Dwemer spheres.
Even with the item set Curse Eater, things weren't going so well.
Although groups could complete vHoF boss 1 with an incredibly antiquated and slow strategy, the issues did not end there with some reporting Purge was not working on vHoF boss 4 - the Refabrication Committee.
What Next?
Most groups assumed that it was just vHoF experiencing the Purge issue until players started reporting from other instances including Kyne's Aegis that Purge wasn't working in cleansing the poison effect from the Poison Totems on the vKA Yandir boss fight.
Upon even closer inspection of the available player-data from ESOLogs and addons, the Purge seemed to be affecting not only combat Pets but also targeting enemy NPCs themselves or simply being too inconsistent for groups.
Unlike the previous Sanctum Ophidia Stonebreaker bug and probably the Deluge bug on Taleria Hard Mode, this newest bug seems to be tied in more with how Purge works in specific group scenarios rather than it being more of a content-related bug.
It remains to be seen how soon the developers at Zenimax Online Studios could fix this potentially delicate bug but players are hoping it's sooner than later.