Frost infusion quest

Hey,
I was on the last of Shadowedge infusions quest - Frost infusion. I took 4 breaths, definitely saw 4 stacks and we downed the boss. The quest never showed up as complete. I didn’t die and didn’t change the weapon. DK Kortaganna on Pagle. Apr 11 ICC25.
We wiped on the first attempt - was that a reason?