More than one PM server in the environment.
In logs, it was also observed that at some point - PM instances are missing from configuration (on some PM servers there were 2 instances, on other ones 3 instances out of 4 instances).
8. Restart the Password manager service for all PM Servers.
Note : Delete AD objects under PMReplication folder. After deleting, wait for new replication. All instances should appear in configuration on each PM node.