Engines of the nalak'sha quest bugged

Today I was doing the Engines of Nalak’sha quest to finish the N’Zoth chain.
I got to the Engines of Nalak’Sha and to stage 4, however Stage 5 was not triggered,

I did a reload and a relog - still stage 5 would not load.
I reran through tghe previous stages and stage 5 still did not load.

I then abandoned the quest and now i’m stuck.
If I re-enter the dungeon, nothing.
No quest for me at heart.
The Vale region is now full of lvl90 mobs, and is not loading the layer I need for the quest.

Can someone help me?
(I have a GM ticket, but 3 days and 6hr estimated response).

I can’t finish the quest. I have tried 2 times now. This is shameful. A key element is stuck behind a bugged quest.

Support Edit - no need to be disrespectful.

We have an article on the quest.

Make use of Zidormi is change Vale states if you’re having phasing issues. If your issue is with the scenario itself, reset it by leaving it empty for 30 mins.