Why does the exterior trim keep coming inside?

Also if you're trying to figure out how to stop the outer trim from coming inside... first delete all of the outer trim, use the room tool and trace all the rooms with it (it's kind of annoying because you'll have to paint the walls again).. but after that put the outer trim/friezes back on and then if you need to place fences or half walls you can do it by placing one piece and drag it to connect to wall.. this will prevent the trim/friezes from coming inside.