Answer:
For deep beams, I would recommend not optimizing the internal forces, as this reduces the number of non-designable points. As far as I could see, the other points are the singularity points. (Message 5 "Concrete compression zone exceeded" in the concrete module indicates this.)
In this case, it is only possible to discretize these corner areas using a mesh refinement. The non-designable areas are thus reduced. In these areas, you can then additionally define an average region.
