After updating the user organization, some of the users revert back to ROOT after the next Data Update Job (DUJ). 

This has been observed for customers on Snow Atlas. 

This issue seems to occur under the following circumstances: 

If Active Directory (AD) user discover is enabled, the inv.UpdatetblUserImportDiscovery step in the DUJ resets the user organization back to ROOT when the user has recent logon activity in the Active Directory feed (based on the AD_DISCOVERY_ACTIVITY_PERIOD setting) and the DisableAutoEditing setting on the user record is set to false.

Whenever a user organization is manually set, always set the DisableAutoEditing setting on the user to true so that it cannot be overridden by any processes in the Data Update Job.

This is an as-designed feature of the inv.UpdatetblUserImportDiscovery procedure.