After running the AMADMIN_SetPrimaryMS job the Primary MS is either not updated or is changed to NULL.
Ensure that the Name provided in the job properties for the Primary and/or Secondary MS's exactly match the name of the server in the Console.
The Name provided to the KS for the Primary and/or Secondary MS, must match the name that the MS Server is listed as in the Console. If the MS is discovered using its NetBIOS name, then the NetBIOS name must be used for the Primary or Secondary MS name in this KS. If the MS is discovered using its FQDN, then the FQDN of the MS must be used with this KS.