WORKAROUND:
1. Backup the QS_ConnectionList.sql file in the folder:
<Diagnostic Server_Install_Home>\Agent\conf\Package\sqlserver_spotlight\<Problematic Server version folder;e.g 2012
2. Replace the QS_ConnectionList.sql file with the attachment listed below
3. Launch Spotlight Client and open the Sessions drill-down to check if it works fine.
STATUS:
Waiting for fix in future release of Spotlight on SQL Server Enterprise.