The Search - quest doesn't work.

After killing the "Scourge of Heaven" boss, I spoke to the NPC in the nest, but the Obscured didn't show up to pick up some of the weapons. Now, when I play through the quest again, the quest icon on the minimap is still showing up in the same spot, even though it's already completed. Consequently, nothing happens on Arastas Island. What can I do about this?