Well, I just did the drake hunt daily, and im not sure what part of it caused the bug, but tis between 2 options. Either
A. when you go to turn in the daily beat the drake there, jump across ravines on the way or w/e u gotta do to have about a 5 yard separation between him and the quest NPC. ull turn in the Q but hell never disappear, hes just loses the debuff and follows u.
B. Vanish acoupla times on the way to dropp mobs off ur back. I doubt this is what caused it, but thats the only other real variable i had, aside from like 20s left when turning Q in. Cant confirm cuz i cant despawn him or redo Q today.
and as far as i have seen its only happened to me on my server