Doze mode... Ez nem bug, hanem feature... Majd biztos ki lehet valahogy kapcsolni.
When the device enters Doze mode, network access is disabled. Wake locks—an app's request to keep your phone awake so it can do background processing—get ignored. System Alarms (not user-set alarm clock alarms) and the JobScheduler are shut down, too. Pretty much all background processing is shut down. If you've ever put a device in airplane mode and noticed the battery lasts forever, this is like an automatic airplane mode that kicks in when you leave your device alone. In practice, Doze mode kicking in is pretty obvious. We would often pick up a device after it was idle for a few hours, and, without turning on the screen, it would suddenly start receiving notifications. Moving it took it out of Doze mode, it connected back to the Internet, and the phone started receiving notifications.