An Azure service that is used to collect, analyze, and act on telemetry data from Azure and on-premises environments.
Hello David Bogues,
Thank you for your patience. Here's an update for you and anyone else who sees the same behavior.
A platform issue in Azure Monitor Action Groups delayed the activation of verified email receivers. Because of this, notifications for fired alerts were skipped before they were sent, even though the alert history showed the action group as executed. That is why test notifications arrived but live alert emails didn't, and why your message trace showed no record of them.
The product team has deployed** a fix for this **issue. Live alert emails should now be delivered as expected without any changes on your side.
If you notice the issue again, please let us know here.
If this answer helped, please click "Accept" so that others with the same issue can find the solution more easily.