Did you keep the common name (CN) on the new ClearPass RADIUS certificate the same? If you change it (single change character is enough), you will get the results that you see.
Try to avoid changing RADIUS certificates as much as possible, so use certificates that live as long as possible. And if you change the cert, make sure the certificate hierarchy (so root CA) and at least the CN is exactly the same for the new cert.
I see that you have your Onboard CA for issueing client certificates as an intermediate to your enterprise root. That is something I would avoid,unless you have a very good reason to bind Onboard in your enterprise PKI; and understand the consequences like that any Onboard generated certificate has full authority in the enterprise trust scope. I prefer to keep the Onboard CA as a standalone. Makes it easier to deploy, less dependencies, and no worries about unintended trust for onboard client certs in your enterprise PKI.