Manager changes are being reverted back

Summary

After updating manager assignment the change disapprears next day

Content

This is happening for few employees. User changed manager assignment in person management and we can see the transaction in transaction console that completes successfully. User can also see the change in person management. But the change disappears next day and we don't see see any history in per_all_assignments_m table as well. We checked and no background jobs are running. We have retrieve latest LDAP changes running every week.