This could be caused by the computer system not powering down the USB completely during shutdown.
Ensure that the CartCare USB Adapter USB cable is plugged into a USB port on the cart's computer that powers off when the computer powers down. Some USB ports remain powered even if the computer is turned off. In this case, the USB Adapter will not recognize that the computer is powered off and will not take over the task of driving the LEDs on the gas gauge.