My G4 just got delivered an OTC update (V30c-FEB-11-2016, not sure why I just got it now), that contains the troubling text:
The battery will now be optimized automatically when the phone or apps are not in use for a certain period of time. Alarms may not sound and notifications from apps that are not updated to the latest OS version may not be received during battery optimization.
What exactly is the alarm behavior if it happens to fall on a battery optimization? How long does a battery optimization session take, and will the alarm sound after the optimization finishes?