OptionFILTER_ALERT_EMAIL_TRIGGER_LIMIT
Description Sets a maximum limit on the number of email actions that can be triggered by a single filter alert within a specific time window. Filter alerts are limited to a maximum of 15 triggers per minute for email actions.
Default15
Minimum15 triggers/minute

This variable allows to configure the limit on how many times Filter alerts with one or more email actions attached can trigger per minute. The maximum value, and the default, is 15 triggers per minute. If a filter alert uses multiple actions, 3 for example, each event — even though being sent to 3 actions — only counts as one trigger.