mapi_current_pending_csr metric is always set to 1 in OpenShift Container Platform 4.8

Issue

• After installing or updating to OCP 4.8 it was found that mapi_current_pending_csr metric from openshift-cluster-machine-approver is always reporting one, even though no pending CSR is reported:

  $ oc get clusterversion
  NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
  version   4.8.12    True        False         43h     Cluster version is 4.8.12
  
  $ oc get csr
  No resources found
  
  $ oc exec -c machine-approver-controller machine-approver-XXXXXXXX-XXXXX -- curl -H "Authorization: Bearer XXXXXX" -k https://localhost:9192/metrics | grep mapi_current_pending_csr
    % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                   Dload  Upload   Total   Spent    Left  Speed
    0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0# HELP mapi_current_pending_csr Count of pending CSRs at the cluster level
  # TYPE mapi_current_pending_csr gauge
  mapi_current_pending_csr 1
  

• Why is mapi_current_pending_csr constantly reporting 1, even though there is no pending CSR?