Hi @ZoltanKocsis, let me see if I can help out here.
Have you tried using different chargers on your XZ premium to see if the behaviour persists? Also, are you charging your phone using a wall socket or a computer as power source?
It is always best to use an original Sony charger and USB cable specifically intended for charging your device. Other chargers may be too weak or too strong as they may have a different electric current rating (mA). It is recommended that you use a charger that is plugged into a wall socket instead of using a computer (and USB cable) to charge your device.
You should also make sure that the charger port is free from lint, dust and moisture. A blocked port can prevent the USB connector from fitting properly, and therefore prevent charging. Ensure that the USB port is completely dry, and gently remove any lint or dust using, for example, a wooden or plastic toothpick.
Another thing that you can try is to reboot your phone to safe mode in order to see if this behaviour persists there. All apps downloaded from Play Store is temporarily deactivated while in safe mode and by doing this, you can see if this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
Try these measures and let me know how it goes!
