It was found when testing OCP-71263 and regression OCP-35770 for 4.15.
For GCP in Mint mode, the root credential can be removed after cluster installation.
But after removing the root credential, CCO became degrade.      

4.15.0-0.nightly-2024-01-25-051548

4.15.0-rc.3

    
Always    

    1.Install a GCP cluster with Mint mode

    2.After install, remove the root credential
jianpingshu@jshu-mac ~ % oc delete secret -n kube-system gcp-credentials
secret "gcp-credentials" deleted     

    3.Wait some time(about 1/2h to 1h), CCO became degrade 
    
jianpingshu@jshu-mac ~ % oc get co cloud-credential
NAME               VERSION       AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
cloud-credential   4.15.0-rc.3   True        True          True       6h45m   6 of 7 credentials requests are failing to sync.

jianpingshu@jshu-mac ~ % oc -n openshift-cloud-credential-operator get -o json credentialsrequests | jq -r '.items[] | select(tostring | contains("InfrastructureMismatch") | not) | .metadata.name as $n | .status.conditions // [{type: "NoConditions"}] | .[] | .type + "=" + .status + " " + $n + " " + .reason + ": " + .message' | sort
CredentialsProvisionFailure=False openshift-cloud-network-config-controller-gcp CredentialsProvisionSuccess: successfully granted credentials request
CredentialsProvisionFailure=True cloud-credential-operator-gcp-ro-creds CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found
CredentialsProvisionFailure=True openshift-gcp-ccm CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found
CredentialsProvisionFailure=True openshift-gcp-pd-csi-driver-operator CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found
CredentialsProvisionFailure=True openshift-image-registry-gcs CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found
CredentialsProvisionFailure=True openshift-ingress-gcp CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found
CredentialsProvisionFailure=True openshift-machine-api-gcp CredentialsProvisionFailure: failed to grant creds: unable to fetch root cloud cred secret: Secret "gcp-credentials" not found

openshift-cloud-network-config-controller-gcp has no failure because it doesn't has customized role in 4.15.0.rc3

 CCO became degrade

 CCO not in degrade, just "upgradeable" condition updated with missing the root credential

Tested the same case on 4.14.10, no issue