Reposting my version of this bug from another thread:

This side quest has been historically buggy. But can't find a solution to my issue anywhere on the web so posting it here.
Zone; Grathwood
Quest: Keeper of the Bones
Protag NPC: Dringoth
USEP has summary of quest here:

Took on this quest several months ago and got as far as assembling the skeleton NPC. Then dropped/deleted it from my quest log. Fast forward several months since and everytime I visit/fast travel to Grathwood, this skeleton NPC always reappears with the follower icon over his head. Apparently the game still thinks I'm on quest with this NPC. But no evidence of this quest exists anywhere in my quest long i.e. don't currently have any quests in Grathwood atm

Is there a workaround for killing this quest? Or if not, how to restart the quest to complete it? The NPC stalking has become quite maddening of late

And yes, the NPC never leaves you alone. He's been continously stalking my PC whenever I'm near or at the Bones Orchard location on the map. As of today when it happened for the millionth time, I got a Dragonguard quest from the Dragongaurd bartender in Southern Elsweyr. Had to retrieve a quest item inside the Bone Orchard delve. And quite unsurprisingly, Dringoth immediately materialized beside Mirri the instant I teleported into the vicinity of the Bone Orchard area. Lol