The client sometimes may take longer to pull it's updates after not being powered on for some time. While the computer is being used by the user, if the client is running with definitions that are older than the date specified in the policy, a popup will appear nearly every minute and taking focus on the screen. There needs to be an option to snooze these alerts, similar to the snooze option that is available for scheduled scans. Disabling the alert or increasing the number of "Days before a warning appears in Symantec Endpoint Protection" are not acceptable solutions in my case.
The policy where these existings and possibly new setting would be in the SEPM->Policies->AV/AS Policy->Misc->Notifications