This is usually caused by battery calibration or a minor firmware glitch. To fix it:
Restore the firmware: Go to code.circuitmess.com and click Restore firmware
Full charge cycle: Leave the device connected to USB for at least 2 hours to fully charge, then use it until it powers off, then charge it again
Check the USB cable: Some cables are charge-only and may not provide enough power. Try a different cable
If the issue persists, the battery itself may need replacing. Contact us at contact@circuitmess.com — we can send a replacement battery.