its kinda buggy yes, sometime the q doesnt work,
i just finished it by chance i think by killing one guy
that was there from someone else, anyway try couple of times if doesnt work, try it other day or something
"Only way I can get this task to work is to intentionally fail the protect the well part. Then you can go get the cure from the priests and be done with it.
Quickest way is to die at the well when first attacked.
I've managed to not die by killing the two mobs that auto-aggro then training the two that spawn in random spots around the town onto the well with a swift horse. This will, sometimes, cause the protect the well step to fail. Still faster to just die."
Invino's solution is better than mine, but i will explain it anyway:
You start the quest, then, 2 mobs will come to you, and you kill them. And the trick is to log off from the game, and log in again. After you relog, you can pull the 2 mobs that are stuck, and move a little close to the quest giver to kill them. The next couple of mobs will spawn & run to you. You kill them, and the quest is complete.