It's a sensor that's on charger port on original called "thermalmoniord" this sensor is not on the generic charger ports that are sold. The "thermalmoniord" when missing the phone counts down 3 minutes then reboots.
The way you can check if it's the sensor it's looking for is look at the error log on the phone or keep locking and unlocking the phone. If the phone doesn't reboot it's because the generic charger port don't have a thermalmoniord sensor on it.