Firewatch TG, last mission where you have to return the stone of septimia, the guard at the entrance forcegreets you right at the door upon entering the museum, leaving you no chance to be caught by the other FG guard at the bottom floor, which is the only one you can convince to stay here at the lower floor, by telling him you have the college's headmaster's permission.

After that, you can normally proceed to cause a distraction by breaking the Kamal bone fragment exhibit, maybe pop an invisibilty potion/spell and sneak unhindered to the top floor.

Solution: Pralec suggested that the guard on the top floor should probably have an elevation requirement on his forcegreeting so he doesn't talk to you unless you come upstairs.

Maybe some additional testing of this route is necessary after adding this condition.