I’m also having this issue trying to get my evoker through Shadowlands to unlock flying. I have looked all over the internet with plenty of people having this issue but not finding any solutions posted. I contact customer support yesterday and they gave me the standard response. I tried what they suggested but it still didn’t work. I will wait to see what they have to say. If a solution is found I will update this thread.
I was able to proceed without this quest and unlocking flying by continuing with a quest I had that returned me to the maw. I can now fly in SL but still can’t complete this quest. I also just hit another wall with the quest “Step Into the Light” where I can no longer proceed with the SL content as it’s doing the exact same thing reported here. Bug Report for that quest is here Quest: Step into the Light