I can no longer continue in the dawnguard quest, as gunmar wants me to kill a bear thats already dead. (I already cleared this cave during an Extermination quest for the compainions.)

Ive tried everything i can think of, and all of the suggestions have fallen short. Really dissapointed.

On a side note, if the game knew i cleared a certain cave of bears, WHY WOULD THE SEND ME BACK THERE FOR ANOTHER QUEST? I thought the radiant story was supposed to base your missions on places you havent been?