Description:
Finished the keep quest a good while ago, all upgrades are active already. But some days ago on entering the great hall I noticed the door leading to the dungeon stairs is closed again and the throne statue is no longer interactive. Trying to open the door resultis in "unlocking this will require the proper key".
I'm still able to enter the endless path of Od Nua via the chapel side entrance.
Caused by:
Don't exactly recall it, but it might be caused by leaving Kana at the keep in excange for the Grieving Mother.