Do Elastic Anomaly Detection Rules Actually Work?

Question

I'm evaluating Elastic (ELK) machine-learning Anomaly Detection. Seems to work great. But I can't get the associated "Rule" to work, that's supposed to send an email.

Has anyone ever seen an ELK Anomaly Detection Rule actually send an alert?

Thanks!

I have made other Rules work, and send me an email. And I can Test the Rule itself over a time frame, and it reports it found anomalies. The Job itself says it found anomalies. But the Anomaly Rule itself always says zero alerts were generated.