Ancient Mana quest not available after faction chance

Hey there o/

I’m having a problem with the quest Ancient Mana on Shal’Aran. I have unlocked Nightborne already while I was Horde so I assume I had completed the quest already, sincei it’s part of the quest chain to unlock Nightborne (as far as I’m aware) but, after faction changing and realm transfering since then, it seems that I need to complete the quest again.
It shows up on the minimap when I hover over and it is flagged as not completed when I run the quest id to check. However when I go over to Shal’Aran, as I’ve completed the storyline already, Thalyssra that will supposedly give me the quest, is not there and is instead in her end-of-storyline place without a quest.
I would like to grab a Mana Divining Stone for reasons but I can’t get the quest, can’t grab a new one from the NPC because the quest is flagged as not complete and right now, I’m stuck in an endless loop.

Any help would be greatly appreciated.