May I know what does the Security Alert Notification mean?
This is from tamper protection. See these KB articles:
This notification triggers upon any of the following security events:
Network Threat Protection events
Device control events
Application control events
You can modify this notification to specify the type, severity, and frequency of events that determine when these notifications are triggered.
Some of these occurrence types require that you also enable logging in the associated policy.
See these forum threads about tamper protection as well:
SEP Firewall "Did You Know...?" - How To Monitor Web Traffic