It's March 2018 by now and this bug is still a thing. Just discovered it today at the Landgraab IX Apartment. In the 2nd story, a few of the exterior textures get deleted, regardless how you edit the inside. It does only aply to the area @nathangecan mentioned and only (at least for me) when the room connecting directly to it gets edited.
It doesn't seem to be solved yet, does it? Or does it have at least a workaround?
