Not sure which issue you mean.
If you mean the GPS issue, I don't remember too many interference related GPS issues in the Q500 series. I do remember many such issues in the Q500's smaller predecessor, the Blade 350QX. Very similar electronics, with a whole lot less distance between them.
If you mean the issue of a difference in the camera mount, I've worked with a good many Q500 and Q500 4K. I have not seen a Q500 4K that came from the factory without the hot shoe. I have seen mods that added the hot shoe to an original Q500. It would be easy to remove the hot shoe from a 4K, or install a 4K shell on an original Q500.
Are you the original owner? Did your kit come from the factory as-is?
The lower shell label on yours clearly says 4K. But the camera mount is the type from the original Q500, non-4K. There is no way to tell from the pictures if the extra bit of wiring to support the 4K mount is present inside the shell. However, there is not a lot of functional difference between the two versions of the drone. (Mainly in how the camera is powered and how the GUI/receiver is connected to the main board.) None of the model related differences sound very related to your GPS issue. The real difference between the kit versions was the camera.
The absence of a problem when you mount the CGo2 currently leans the thought trail more towards either the camera or the CGo3 pigtail.
1.) If you have access to another CGo3 and CGo3 pigtail, it would be great to try a different camera on yours to see if the issue goes away.
2.) If not, the absence of the contacts on the CGo3 in your picture may suggest the next step. You could pull the dampers and remove the gimbal board enclosure to see if the three black wires were properly removed and/or if the solder pads associated with the wires are damaged. If the dampers ever came out in a crash/hard landing and the camera was powered up again before properly removing or repairing the three black wires, the list of possible damage/symptoms pretty much approaches infinity.
CGo3 Removing the Three Black Wires
3.) Another/next reasonable next step would be to remove the top shell to ensure the heavy copper foil is protecting the GPS. Also to look for any damaged/crushed wires anywhere in the drone.