[REJECTED] Meryl Felstorm NPC disappeared while doing a quest for the mage artifact

[Tarnien]

Wowhead quest link: http://www.wowhead.com/quest=41125/unlocked-potential
WoW Freakz quest link: https://www.wow-freakz.com/quest_helper.php?quest=41125&name=unlocked-potential
Bug description: I was doing the quest and kept switching between specs to see differents artifact styles and traits, and all of a sudden the npc, Meryl Felstorm disappeared, so i cant turn it in. i tried logging out and relogging again, i tried reloading the hall of the guardian, i even tried abandoning the quest, so now i'm stuck out of my artifact questline.
Proof: https://imgur.com/40ana9H

EDIT: I opened the game after some hours, and the npc was there, i managed to do the quest. I'll leave this post here just in case u wanna look at this bug.