While in the temporal sanctum, monolith quests do not generally show up - but when this bug happens, its almost as if you get put in the ancient era and the monolith quests suddenly show up upon loading into the next zone.
Can confirm that this has happened to me multiple times, 2/2 attempted clears the final door can’t be interacted with. Hovering it highlights the door, but I can’t interact. I had the same issue with the first door of lightless arbor previously.
Has also happened with me in Soulfire Bastion. Got to an enclosed room where you read a note, and couldn’t open the door to continue. I’ve seen reports on the same issues at least months ago. Sort of a game breaker for me until they get it figured out.
My group can re-create a very similar bug in multiplayer. If one person has any UI open, especially an interactable object like a book and a second player interacts with a dungeon door for the final boss encounter such as Julra, no one else will get the dungeon door pop-up.
Any chance you clicked on any books or talked with NPCs right before entering this area?