Two Alert Emails - one silenced, one not

We are using Grafana to view primarily Prometheus data. We have multiple Prometheus Exports on each host. I’m generating email alerts when some exports on a host are working, but not all. This all works, but two emails are generated, not one. The emails are received at the same time. One email takes into account silences, the other does not. E.g.

In this case there are 7 systems alerting, 6 of which have been suppressed:

Both emails are going to the same contact point. There are two email addresses being targeted, and we are using the “single email” option:

Any ideas what I may have got wrong?