Two of my friends have broken rj45 sockets in their kemper racks. They still work, but they don't hold the cable tight(yes, cable and nose is ok, its the socket). This can happen when someone accidentialy pulls hard on the cable while plugged in.
It is possible to change them. But you have to disassamble the whole unit to get to this point, and have to solder the small connectors.
If you don't live in the US getting the spare part costs about 35€ or more, cause you only find shops in the US that sell them.