You might try carefully cleaning the central contact tab on the keyboard with some rubbing alcohol on a q-tip or cloth. I use a q-tip, dip it in the alcohol, and then blot in on a paper towel so it's not too wet. Then gently clean the gold contact area on both sides. Then dry any excess moisture. My surface book was dropping the usb any time I touched or repositioned the screen. Cleaning the contacts solved it completely.