Since December 2, 2017 my Apple iPhone 7 plus showed a crazy behaviour. If i work in an App, the device unexpectedly showed the circle that we know from booting up the device. After a few seconds, the device is in standby mode and we can press the home button to bring it back to normally conditions. The app who was opened before was closed afterwards. The device repeated the same thing every few minutes. In fact i was unable to use my device normally. I decided to call the apple support.
While i was waiting in the queue to become a technician, i heard a voice who explained that this is a known issue since December 2nd. And i got redirected to the Apple Support Article HT208332
If your iPhone, iPad, or iPod touch unexpectedly restarts
If your device with iOS 11 unexpectedly restarts repeatedly on or after December 2, 2017, learn what to do.
If you can’t update, turn off notifications for all the apps on your device, then update your device to iOS 11.2:
- Tap Settings > Notifications.
- Tap an app, then turn off Allow Notifications. Repeat this step for each app.
- Update your device to iOS 11.2.
- After updating, tap Settings > Notifications and turn Allow Notifications on again for each app.
If you’re unable to update or still have issues after the update, contact Apple Support.