"SQL Diagnostic Manager Service Status" metic

This has probably been asked before but I could not find anything doing a search.

When setting up Alert Responses, there is a prebuilt one called "SQL Diagnostic Manager Service Status". This response has the metric of the same name selected, but when I updated it to send emails to my configured SMTP account, I get nothing.

When I create a new Alert Response and configure everything the same but exclude the "SQL Diagnostic Manager Service Status" metric, the alerts get emailed as expected.

Why is this?