Thanks, good to see what you're looking at. Damn white PCB though, hard to follow any traces so I'll have to assume the lower switch pin is conncted to the diode below it.
I think the next step I think is to take off the diode. If the short is at the switch end the pads will still be shorted, if the problem is hiding elsewhere (under the controller chip?) they won't because there's a break where the diode should be. Assuming this confirms the break is at the switch end the next question is do you just want it working or working and looking perfect from the back of the board?
I say this because the easiest fix would be to insulate the lower pin on the switch so it doesn't connect to the PCB and turn the diode so only the end not connected to the switch is soldered on. Then you can solder a short wire from the end of the switch pin to the other end of the diode bypassing the shorted trace. You have a plate so the switch won't be able to twist and will hold the switch when you're pulling keycaps off, from the front you'd never know the difference... If you're planning to open the board up or transport it often you would want to add a drop of hot glue or similar to hold the diode in place but if it's just sitting on your desk it's not going anywhere.
The other option (if the short is confirmed to be at the switch end) would be to desolder everything and hope there's a visible short on the other side which you can fix.
If the short is at the controller end you probably need to speak to the GB runner or Leeku to get a replacement, not sure how you stand having taken the diode off though. It's clearly not been abused so I would hope it's not a problem but "modifications" usually end any warranty.
Almost certainly unrelated but it looks like your screw in stabiliser for Enter is shorting two LED pins, a plastic or card washer would be a good idea if it is.
