When an alarm is reposted by an Auto Operator nas rule that has 'action mode' set to "overdue age" it will not include the 'event_type" field in the reposted udata, while if the same alarm is reposted "on arrival", it will include the "event_type" information.
Is this the expected behavior?
Yes, this is working as designed.
For the action mode 'on_overdue', the alarm is being fetched from NAS_ALARMS directly and it doesn’t read in the event_type. The reason for this is because the NAS_ALARMS only stores the latest event_type so if some other auto-operator performed an action on the alarm, the event_type might no longer be what it was that triggered the on_overdue timer to start.
For the action mode 'on_arrival' instead , the alarm is coming directly from NAS_EVENTS which is populated from NAS_ALARMS by a database trigger.