event QUEST_ACCEPTED getting weird arg

[Kanegasi]

The first arg given to every function attached to a frame with setscript is the frame itself.

QUEST_ACCEPTED has only one return on retail: the quest ID.

Blizzard didn't change anything, that "user data" is the frame you registered the event to. Somehow you changed something, most likely a simple : to . in how you handle events, which caused your first arg to be the frame instead of the quest ID.