it seems the sensor for battery have problems... have you try to see battery capacity via BIOS by pressing F2 at boot...?
try install this ASUS Battery Health Charging https://www.asus.com/us/support/FAQ/1032726/
It will help the battery life span too. Once my GL702 always 100% fully charging and it got swollen and gave some strange effect on touchpad, keyboard.
now, i set it only to 60% capacity for max life span.
Hello tzw0perator ,
Please kindly send your device to service center for further examination.