Easy to check and see from this window

 

From a map list or map, go Window – Device List

This is every device on every map you are monitoring and sending alerts on

There are 3 icons in upper left hand corner of window

The middle icon is your alert settings for each device

When you click on it, a drop down text box appears with all alerts defined

Click on the drop down box and select the alert that is sending

This will show you all the devices that are using that email alert

To stop sending, just uncheck the box on the alert of that device

There also delay, repeat and count selections that you can change

Perhaps the alert has been set to repeat forever

From the alert you should be able to tell what device is getting monitored