Just got this bug. I have a suspicion. Before i did the Farmers Plight, I attempted Siege of Craghodt. There, I saw kograk and went ahead to kill him, forgotten that he is involved in the Dryford quest.
So when I got the quest, I got a message that the quest had been resolved. Going into korgrak cave though, i can see him and having same bug as everyone here. So, Obsidian, can you please either:
remove korgrak from Craghodt so I dont need to kill him
or, find a suitable way to complete the quest when korgrak already dead
EDIT: My bad, it was not kograk in craghodt, it was Crothar. So the bug has nothing to do with WM