Don’t know if this is a bug/feature/weird thing.
When extruding a simple rectangle SOP, the normals are pointing inwards on the new faces. When compute normals is selected it all just looks a bit wrong, like the the normals are computed at 45 on each corner.
Could there maybe be a “flip normals on extruded surfaces” option. the points SOP with add normals set to *-1 works but then you have to run it through a merge to get it all back together.