Thank you so much! It worked for me too!
Weirdly, War Mode hasn’t worked for me. Still the same issue 
War Mode worked for me, thanks!
Turning on war mode worked for me. Thank you!
Having the same issue. Thought about abandoning and trying again but that hasn’t worked for folks anyway.
Had the same issue but turning on War Mode worked!!
Happening with me as well, I’ll give the war mode thing a try tomorrow but nothing else has worked so far, so I’m not super confident
Turning on war mode allowed quest to be handed in.
Today the quest worked! Not sure if it was because a day had passed or because I took down the rare Colassal and then went to turn in the quest.
I had to fly up to the top of the towers to find Ebyssian waiting on the roof of one of them nowhere near the quest marker.