Due to a silly error on my part, I suspect that in a lot of places you'll run into doors that appear to have a transition despite just opening to a room or being in the middle of a hallway or something. Please report where you find any messed up doors like that in this thread.
Room Three in the House of Heroes had this bug last time I checked.
In the Gound Residence next to the work mill, it's the door on the left as you enter.