Google Systems updates for April include a new security feature. If you leave your Android phone or tablet locked for three consecutive days, your device will automatically restart. You’ll need to re-enter your passcode to open the device.
The latest Google Play services update is designed to better protect your data when you aren’t using your device. It’s the latest addition to Android’s built-in security and privacy features.
Android’s forced restart is basically a way to keep your data safe without forcing you to power off your phone, which many of us rarely do for days (or weeks) at a time.