MachineConfigPool degraded: content mismatch for file "/etc/containers/policy.json" in RHOCP 4

Issue

• When upgrading RHOCP 4, the upgrade can stall waiting for the machine-config operator to return to an Available state, while a node is kept under Degraded status.

• The following error appears when running oc describe clusteroperator/machine-config:

  Operator: 'machine-config'
      Issue: Degraded
      Reason: RequiredPoolsFailed
      Message: Failed to resync 4.10.43 because: timed out waiting for the condition during syncRequiredMachineConfigPools: error pool worker is not ready, retrying. Status: (pool degraded: true total: 8, ready 3, updated: 3, unavailable: 5)
  

• The following error appears when running oc get co machine-config -o yaml:

  message: 'Unable to apply 4.18.21: error during syncRequiredMachineConfigPools:
          [context deadline exceeded, error MachineConfigPool worker is not ready, retrying.
          Status: (pool degraded: true total: 3, ready 0, updated: 0, unavailable: 1)]'
  reason: RequiredPoolsFailed
  type: Degraded
  

• The following error appears when running oc get mcp worker -o yaml:

  pool is degraded because nodes fail with "5 nodes are reporting degraded status on sync": "Node worker5.ocp4.example.com is reporting: \"content mismatch for file \\\"/etc/containers/policy.json"