Quest: https://www.wowhead.com/quest=8488/unexpected-results
The ambush happens, but after i kill the mobs, i don't get the credit, and i can't turn in the quest.
I cleared cache, logged back in, still couldn't turn in. After i abandoned it, i couldn't accept it again from the NPC, because the quest wasn't available anymore.
Edit: For some reason after some hours of not playing i logged back in to the game and the quest was available again (still doesn't work though)