Main scenario stuck

I am on the main scenario mission "Rock-Solid Protection" where I need to use the Duty Finder to enter the Sunken Temple of Qarn (Hardmode). I've completed this dungeon twice with the quest active and it will not complete. I don't know if it's due to being a main scenario quest but I cannot abandon it and restart it. I've also done the dungeon once after completely logging off and back on.

It's normal version of the Sunken Temple of Qarn, not the hard mode.

Umm, this quest is for normal mode Quarn.