SEP 12.1 RU6 has been released & has a bug related to File repuation alert, check if it's applicable in your case or not however I would suggest you to upgrade to SEP 12 1 RU6.
File Reputation Lookup Alerts send malformed emails when triggered
Fix ID: 3713171
Symptom: File Reputation Lookup Alert notifications created after the install of Symantec Endpoint Protection Manager 12.1 RU5 sends incomplete emails when triggered and does not include details about why this email was sent.
Solution: File Reputation Lookup Alert notifications are now created correctly and generate the expected email report.
Reference: New fixes in Symantec Endpoint Protection 12.1.6
https://support.symantec.com/en_US/article.TECH230558.html
Upgrading or migrating to Symantec Endpoint Protection 12.1.6 (RU6)
http://www.symantec.com/docs/TECH230601