As said above, at the Imperial Archaeological Society's basement one of the common interior pieces is just missing at the dining area. Seems somebody might have accidentally deleted it.
Drala Uval, a vendor at a stall in Hlan Oek, claims to be selling weapons but no items appear in her barter menu. None of the weapons sitting on her stall table are considered owned either, allowing the player to loot them for free.
If you lockpick the doors inside the Zafirebel Bay Company to get into the upper or lower floors, you'll find the door you just unlocked is locked from the other side as well. This could cause the player to get soft-locked because many of these doors are lock level 80+.
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.
