Icom 706mkiig separation cable problem

I have a 706mkiig and am using 3D printed rj45 adapters for separation cable. The trouble is, I get a tic tic noise on transmit. If I put the faceplate back on the radio, the noise is gone. Now, mind you, it does the same thing on 3 different 706 radios. The cable I’m using is shielded too. If I use the original separation cable, the noise is gone. Am I missing something here?

I’d double-check the electric connections between homebrew and stock cables.
Does this depend on TX power?