good catch.
I analyzed the built geometries with different CADs (DSM, VariCAD) but I didn’t found any issue…
Only analyzing the single transformer I get the errors in the geometry
Not even a FreeCAD issue probably, but the issue is in the boolean Cut operation done on the transformer inside FC…
Anyway, each CAD STEP parser has its own peculiarity…
For that reason a well formed and checked MCAD library is a must for KiCAD.
It is enough to have a single wrong model to mess up the all assembly result.
That is why we put a big effort on the 3D model library at GitHub…