This may have been already mentioned, but whilst doing the Dawnguard questline you are sent out to recruit someone name Gunmar. When you find him he's tracking a bear he wants to kill and asks you for help. So I go to the cave that is marked as having the bear he's looking for in it. And when I do I clear it out from any and all creatures including bears nothing happend. The marker for the bear he wants doesn't clear and instead just sits on the ground. And I can't progress the questline because he still wants to kill a bear that isn't there. Any ideas, cause this is sort of ridiculous?

Well then....go to a previous save.

I've tried a couple, but not sure how far back I gotta go. I have one right before the Volkihar castle, but I've come a long way since that. I took several detours working on several other things and I don't really feel like doing them over.

This is probably better in the Spolers section.

But my tuppence: have you tried leaving the area and going back in?

Sorry, I didn't think there was any major spoiling that people would care about. None the less, I've tried going in and out and even waiting several days outside the cave before going back in. Still nothing.

Well I know the problem. It's because the cave is marked "Cleared". It must've been before I started this quest, or maybe it was during even, where I did an animal extermination trying to get Aela to give me a Totem of Hircine quest (which also is glitched). Once the caved is marked "Cleared" that is when it's glitching out. I went to a previous save which was 14 hours ago when the cave wasn't cleared and everything was working fine. Looks like I'm losing a lot of work.

Oof. I feel your pain.