Alerts when [OK] or [No Data]

Hello all,
I setup an alert on some graphs with the following parameters:
“when last() of query (A, 5m, now-245m) is outside range -0.5 to 0.5”
to trigger an alerting state and send it via email.

It works but I meet two issues:

  • In case new “OK” points appear, or past “NOK” points get too old, the alert stays in “Alerting” state on my graph.
  • I sometimes get alerting emails, with “No Data” or “OK” points

Do you know what might be causing these issues ?

PS:

  • I setup “now-245m” as my data is UTC-5 and I am UTC+1, so it should be looking only 5 minutes into the past.
  • “If no dara or all values are null set state to No Data”
  • “If execution error or timeout set state to Keep Last State”

Regards.

UP.

Has anyone seen a similar problem?