I'm supposed to get the key from Bearclaw cave. I can see the quest marker on the floor, but there's no damn key anywhere to be found around it. I tried looking for the quest ID so I could reset it, but it's not documented anywhere I could see. Any fixes?
Not all quest marker mark the direct item. Some markers just mark the vicinity of the quest, where you have to find the item yourself.
As explained by the wiki:
The monastery entrance can be found by going across the top of the burial mound and down the steps. Once inside, either turn left or right: both passages will lead to the same location. Thorlogh will open a secret passage behind an old crypt that leads into a mixture of tower and Nordic ruins. After following the passage, a Necromancy Leader will exclaim at the visitors: Thorlogh will explain that they're under the command of Vernan. Fight through the various Necromancers until a large open area is reached: the Key is through the door on a pedestal, surrounded with loot.
I found it in the table to the far left, behind the mead keg. It looked (to me) like an ordinary piece of gold, so I also overlooked it, instead using Unrelenting Force, Fireball and whatnot on the ground. Perhaps that's what's happening with you too. Sure, the quest maker DOES point to the rocks, but it's not there! Look where I directed you. Happy playing! ;-)