We have ArcGIS Server 10.4.1 federated with Portal running on Windows 2012 R2. One of client (Publisher role) published a map service in server and layer item was created in portal. When he tried updating service - just changing label and overwriting the existing service, duplicate portal item was created. The client was original owner of portal item at the beginning (ensuring he was not updating others contents) . He uses ArcMap for publishing with same credentials and everything is same. User is not altering any security settings in portal.
I would like to understand what are all possible scenarios for duplicating the portal items?.
Please provide more insights on this case.