Shoot, I don’t know what the issue is then. Maybe it could be an EC problem, I also had an issue with that, but I’m not sure 100%: If you go into BIOS, there should be an option for battery disconnect. You can select it and exit saving changes while on battery, which will disconnect it momentarily. Then, wait for about 5–10 seconds, then plug in the laptop and boot if off of AC power.
I hope that it works!