Currently 'working as designed., populating the alarm with the e2e_appmon probe name is not supported by the API calls, e.g., nimAlarm or nimAlarmSimple
In the probe field, it shows UnknownProbe because it comes from within the script using the API function which does not allow specifying the probe name.
It is simply not part of/included in the e2e_appmon API functions.
This would qualify as an enhancement request.
Please refer to the e2e_appmon API techdocs:
Suggest entering an enhancement request to have nimAlarm and nimAlarmSimple API calls enhanced to set the probe name.