I filed 2 bug reports about this, but maybe someone here knows a workaround.
The Ascendant Storm- I killed the magus, left the room, but the "kill the magus" quest didn't clear. Everybody was in the room with me (as they would when you finish defeating him), and he was still there in the center with his boss bar full, but couldn't attack him. Tried all the things and relogging. Still like that. Traveled away and the quest progressed to "Exit all flags castle"- I go to where the quest marker is- everybody's outside and happy and will talk to me about what's going to happen next, but the quest can't progress because I haven't cleared "exit all flags castle".
Tried all the things again. Second bug report. Nothing works. I'm stuck and there's no way to get back in the castle to get out of it.
I was just grinding this quest to get a stupid card deck.
Any suggestions, even dumb ones, welcome. This may be the maddest I've ever been at this game.