The Descent quest bug?

I had the same issue.  I play on xbox one.  It was making me nuts. Tried fast traveling back to camp and then back, didn't work.  Went back to skyhold and came back, didn't work.  

Eventually what worked for me was to backtrack out the way I came into the area. (not fast travel)  After I got a bit away, the enemies respawned and I had to kill them all again (the ogre and everything else) and then suddenly I could investigate the corpses.