Yes I am seeing the same with my windows (I don't use the Graphisoft ones although mine are based on very old Graphisoft windows (version 6.5)).
I have never had the need for slanted walls with windows so have never noticed.
The inside and outside surface materials are swapped.
The external reveal is the internal surface material and the internal reveal is the external surface material.
Even my external sill adopts the internal wall surface material.
I am not seeing a problem with the wall ends but that may depend on what they join.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11