Recently, the surface has been having an issue where all of a sudden, all of the LED backlights turn off and the surface stops working. You can still see the names on the channels (although not backlit), but fader movements do nothing and buttons such as mute do nothing. The touchscreen remains lit up, but is also unresponsive. Luckily when this happens we usually have an iPad connected so we can continue mixing from that, but it is not ideal. We have to hard reboot the surface to get it to come back. Any suggestions about what the issue may be? Could this be an issue with the cable connecting the surface to the mix rack or do we have a much bigger issue potentially.