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.