In SharePoint 2013, if the NetBIOS name of any domain that you are synchronizing with differs from its fully qualified domain name, you should enable NetBIOS domain names on the User Profile service application.
  1. $upsa = Get-SPServiceApplication –Id < UPSA id>
  2. $upsa.NetBIOSDomainNamesEnabled= 1
  3. $upsa.Update()
The UPSA id identity is the GUID associated with the User Profile Service Application that was retrieved from the Get-SPServiceApplication.
Happy SharePointing :-)