This quest has a huge bug in it.

...

...

...

...

No but seriously, if you go to the mabrigash and convince her to remove the curse, but then don't go straight back to Atriban Deras and instead go off somewhere else until her curse hits you, your quest gets set to stage 110. If you then go back to Arvud, it has skipped past the stages where it would remove Atriban the shalk and add in Atriban the NPC, and the quest becomes unfinishable. Even if the enabling and disabling did work correctly, the dialogue that gives you your reward (in Greeting 5) is set to stages 50-60, so you can't get it if the curse hit you and set you to 110 beforehand.

A possible solution to this would be to move the scripts handling enabling and disabling the Atribans to the mabrigash herself instead, since the player would be around her when the switch needs to happen either way. Or just add exceptions for when the player is already at stage 110 to the scripts and reward dialogue, or change the journal stage from 110 to a lower one.