False Alerts firing

Hello I’m using Grafana v4.4.3 (commit: 54c79c5), with Graphite on Ubuntu.
I’m having problem with false alerts.
I have an alert set on 1 but sometimes it triggers with a higher value.
The alert is on the yellow metric, and as you can se it never goes under 1.
alert

Thanks

did you check the alert info, maybe it was due to graphite returning an error or null data?

I’ve changed the alert to skip the last 5 minutes and now it’s ok.
Thanks