Keeping The Darkspawn Down Quest Glitch

One of the stones can't be energized and moved into location to finish the quest. I tried to take a screenshot to show where but no luck. The location is on The Storm Coast, the cave with two entrances that leads into one larger room. I checked walkthrough's and video walkthroughs that show that this is where the quest is completed, but I can't complete it for some reason. I can't interact with the stone.