I collected what was needed for the quest and the fight I did the collected stuff along with the quest vanished.
No message of completion in chat either.

I am not sure whether I got rep for it.. but the missing message in chat and the fact that I didn't click finish and wanted to gather on for extra, which you simply can't is quite enough to report this for me... Especially since you can't do anything else as a defiler.

Asked others about their quest, this seemingly didn't happen for anyone else..