Problem exporting STEP file from CAD Assistant and importing same STEP file

Hi, I have a problem exporting a STEP file from CAD Assistant and importing the same STEP file again (see screenshots). The shape can somehow not be reconstructed from the STEP file. The source is a BREP file which I open in CAD Assistant and then export as STEP file. My guess is, it might be a problem with OCC STEP export. Source BREP file and screenshots of the BREP file and STEP file opened in CAD Assistant are attached. Cheers, Tobi