This is a fairly common problem with the FM3. There have been a number of posts describing this problem here on the forum. Mine also broke after the warranty period. I did not attempt to fix it myself, so I am not familiar with the soldered PCB standoff shown in your pictures. It does seem odd that it would be soldered to the chassis. Perhaps this was done for stability, to prevent the PCB from working loose or to improve grounding.
I am guessing that some of the connectors have a weak plastic center that is brittle and breaks easily. I rarely used my USB connection the first 18 months that I owned it and I was careful. But one day when I removed the cable, the center core insulator of the female connector broke off and came out in the cable. I chose to send it back to Fractal for repair. The repair turnaround was quick, but it was not cheap, especially with the shipping costs both ways.
The plastic insulator on the repaired connection seems to be a little more solid and so far seems to be holding up well. I still use an extra measure of caution when plugging and unplugging the USB cable. I bought some short extension cables to leave plugged into the back of the FM3 so that the strain from plugging the USB cable in and out is now mainly on the extension and not on the actual connector on the back of the FM3. This reduces the wear and tear on the main connector.
You may have to contact Fractal or your distributor to get this repaired if the repair does not look like it would be a simple procedure. Good luck! Hope you can get it resolved soon.
