"grafana_state_reason: NoData" added to my Slack message even though it is not mentioned in the Alert Template

Hello.
This is my alert template:

{{ define "custom_alert" }}
{{ range .Alerts }} {{ range $k, $v := .Annotations }}
{{ $k }}: {{ $v }} {{ end }} {{ end }}
{{ end }}

This is what shows on Slack:


Any idea on how to remove grafana_state_reason: NoData from my Slack message?
Thank you.