Help!! Back wall keeps disappearing

[WHirsch]

The ceiling plane that extends from the porch up through the second floor is the problem. Not sure why it's there to begin with, since the porch roof is pitched the same as the ceiling, and up above is just attic space. Get rid of it, or edit it to cover only the spaces that need it. After that, you might have a little fussing with attic walls to get everything right, but it should work. As Lew said, there are other issues as well.