In addition to Castle Ravenloft bugs mentioned here:
https://www.arcgames.com/en/forums/neverwinter#/discussion/comment/13193725 with the 1st and 2nd bosses, Strahd's damage has significantly increased with this week's patch introducing Reaper's Challenge. I plugged CR last week no problem. Now we had a group of all 55k+ and could not beat Strahd. No consumables, artifacts, or health regen was not the main issue. Strahd's sword hits and damaging aoes were doing way too much damage, racking up player death heads and causing wipes.