interesting, I wonder why the board has extra two pins.  Is that do to the switch to usb-c? 
(pure speculation)
 in the past my surface 3 would flip out and disconnect the keyboard.  immediately my surface would tell me usb device disconnected.  it might have been the very reason Surface pro wasn't updated to a dedicated usbc port.  Maybe Microsoft didn't update the port because they didn't want to invest in a new keyboard connection... anyways.