It sounds to me like your GPS driver is capable of working off USB also. I say that because it seems like your driver is sending info out to the USB devices “looking” for a GPS. It obviously finds the GPS on the com port but continues sending info out the USB or you wouldn’t continue to have the problem. I don’t know. I just took a stab in the dark. Try uninstalling your GPS driver but leave the GPS device plugged in. Then you would know it is related to the driver only.