When attempting to patch a hostedcluster CRD in order to perform an upgrade, the patch command fails with a CEL validation failure like:

The HostedCluster "XXXX" is invalid: spec: Invalid value: "object": no such key: servingCerts evaluating rule: APIServer loadBalancer hostname cannot be in ClusterConfiguration.apiserver.servingCerts.namedCertificates[]    

    MCE 2.10

   yes 

    1. Upgrade MCE from 2.8 to 2.10.
    2. Create a hostedcluster CRD with no servingCerts under spec.Configuration.apiserver.
     3. Run patch on CRD like "$ oc patch hostedcluster XXXX -n XXXXXX --type=merge -p='{"spec":{"channel":"stable-4.18"}}'"
    

    Patch command fails with "no such key".

    Hostedcluster patched and upgrading.

    A workaround for this is to add a blank structure that the validator expects to see:
oc patch hostedcluster XXXX -n XXXXXX --type=merge -p='{"spec":{"channel":"stable-4.18", "configuration":{"apiServer":{"servingCerts":{"namedCertificates":[]}}}}}'

Looking at some of the validations, it looks like it could be from https://github.com/openshift/hypershift/pull/6091, but not positive.