I was given a quest to check out a tower-bridge and kill some bandit leader there. (I know - pretty much describes 50% of Skyrim quests)
Anyway, I'm sneaking up one of the towers when I see the dude I have to kill walking back and forth along a cliff trying to shoot an Elk with a bow. At one point, he get's too close to the edge and falls to his death. Upon impact, the words "Quest Completed: Return to _____" appears in my main screen.
I never engaged him. I never even crossed the bridge to get to the cliff he was on.
I "completed" this quest by watching this guy accidentally falling to death while trying to kill an Elk.
lol
Intended? Bug? Or just dumb AI?