Open Radar

 
Summary:
When a device has been drained down to 0% battery and has a pending Amber Alert, after the device charges enough to power on again, the extensive vibration feedback from the pending Amber Alert will cause the battery to drain back down to 0% and shut itself off again. This may repeat in a loop, until all notifications have been processed. 

Also noticed during this occurrence is that there seemed to be multiple duplicate Amber Alerts pending, perhaps as a result of a another, unrelated OS bug. These multiple successive Amber Alerts might be necessary to reproduce this bug, however it is possible that this may be reproducible with only 1 Amber Alert notification.

It seems like a potential fix for this may be to implement some 'power-awareness' with regard to how notifications are processed on device boot. Perhaps, in low power scenarios, when the notification queue would require a large amount of power to process (i.e. lots of vibrating, etc) and could cause the device to drain back down to 0%, it would be wiser to defer processing these notifications until later or minimize power-heavy functionality, such as vibrations.

Steps to Reproduce:
0. Queue but do not process an Amber Alert notification in the OS
1. Drain the device down to 0% battery, so it shuts off
2. Charge the device until it turns on again
3. After the device turns on, ensure the Amber Alert is processed by the OS and the device begins to vibrate

Expected Results:
The device remains on and continues to charge

Actual Results:
The device's battery power drains down to the power off threshold and turns off. The device will charge enough to turn on again, process more notifications that may cause it to drain back to 0%, and continue the behavior in a loop.

Version/Build:
iOS 11.0 (15A372)

Configuration:
iPhone 7