https://github.com/openshift/cluster-monitoring-operator/pull/1062 and https://github.com/openshift/cluster-monitoring-operator/pull/1063 set priority classes equal to user workload monitoring (openshift-user-critical). This can lead to unpredicted scheduling behavior during upgrades between in-cluster monitoring and user workload monitoring.
*** This bug has been marked as a duplicate of bug 1934516 ***