When an existing alarm is cleared, why is sometimes the Alarm cleared messages not registered in the alarmnotifier log file?
When an event to clear an alarm is issued, in the alarmnotifier log you should see an Alarm UPDATEd followed by an Alarm CLEARed message.
Now, by default in the .alarmrc file there is: UPDATE_EXISTING_ALARMS=false (Specifies whether to update the existing alarms). With this setting the alarms that occurred and existed prior to the time AlarmNotifier application was run, will be ignored and a clear event of them will not be passed to alarmnotifier to invoke the CleanScript execution.
To prevent this problem set UPDATE_EXISTING_ALARMS=true in .alarmrc and restart the alarmnotifier.