Roof trim that touches the wall disappears and will not allow me to put it back

Building a home in Del Sol Valley and I saved and quit my game mid build.  When I reloaded, my terrain paint had vanished and the roof trim on the main house where the roof intersects the wall (minimal roof overhang) has turned invisible.  It will not come back except if the wall and roof trim DO NOT touch.  The unattached garage has the same roof but for some reason DOES NOT have the same problem!