@ubiexcellent Loading a previous save removed the quest from my list. The avenge quests are online quests related to other players so I did not find another in the area at the time. The core problem is the game telling me to confirm dead and interact with something that no longer exists. It seems I will have to refrain from these quests altogether or stop using the Explosive Corpse skill for now. Perhaps a solid solution would be to make it so exploded corpses either remain after triggering or are automatically tagged confirmed dead.

I received an avenge quest in Winchestre Garrison, but due to using Explosive Corpse skill the quest is uncompletable. In the picture I have included there used to be a booby-trapped dead body where the marker is pointing, but there is nothing left to interact with after triggering so the quest is glitched out.