If the alert escalation any is not checked, the alert will only trigger once (as it stays ACTIVE) until the condition has been reset.
If you want to constantly have this alert notify you, you may want to edit the Alert and then go to Trigger Actions > Select and Edit the Alert Action > Edit Selected Action.
Next, go to the Alert Escalation tab and tick "Execute this Action repeatedly while the Alert is Triggered" and then set the time
Click OK to Submit.
Let me know if this helps.