This issue is on the list as RH-65805 Support selective clipping in Cycles
It’s not something that will be fixed in Rhino 9.0 but could possibly be looked at for a 9.x release.
Note that you appear to be having more luck with the Rendered display mode than I’m. Selective clipping only somewhat works in that display mode as well → RH-84790 Display: Non-Clipped Object is Somewhat Clipped in Rendered
-wim
Really appreciate the information. Thought it was already fixed in some of the earlier SRs. Just realized that it’s still there it while having online sessions with a group of architects.