The bug stated in this US thread from October 2022,
Is STILL present in the game, upon hitting 50% Prophet Skeram will disable 95% of your character’s PASSIVE effects, even things like a Rogue’s Sinister Strike stops producing combo points, it’s actually completely devastating to a lot of classes, me and a friend spent hours trying different ways to solo it (we’re both not max gear, and we shouldn’t have to be to kill a level 60 raid boss at level 85, solo or duo).
Any help reporting this via the ingame bug report would be massively appreciated, personally I will be sending 1 per day till it is fixed, as I spent money on a 2nd sub, a boost and a couple of WoW tokens, just to be able to carry my level 60 Ret Pala through it and I can’t even get past the first boss cause my class stops working properly at 50%.