The new Parasolid version in V12 may handle imported custom parts with PLMsynchro differently than V11.
In this context it needs also be checked if in the conversion process by CAD better STEP or XT should be written.
For some systems STEP is advantageous, for others XT. Furthermore the decision can differ from project to project.
For profiles, Creo does not produce good results with STEP, but with XT.
The change must be made in the Conversion node under Conversion path:
iface.proewildfire,stp,partjava
iface.proewildfire,xt,partjava