[SoZ][Bug][Spoiler] A quest-bestowing NPC can be missing

[IanTheWizard]

In Storm of Zehir, after you enter Dragon Cave to confront the dragons, you would run into the fake escaped Tarmas the Wizard. At this point, if you go back to West Harbor to kill the dragons first and then go to Dragon Cave again and rescue the real Tarmas the Wizard, you won't find Goodwife Aruna after you go back to West Harbor again. In fact, you won't find all the NPC there expect for the real Tarmas the Wizard and the half-drow. Therefore, you can't turn in Goodwife Aruna's quest and can't buy stuff from her and the male merchant anymore. Is there a console code for fixing this bug?