374D injector harness

Looking for ideas on what could cause the injector harness under the valve cover to keep breaking the same wire on #6 injector. History on machine: cylinder head was removed and reinstalled after broken exhaust bolt removed. Overhead and injectors all set at time of install. Soon after, had a break in the harness for #5 injector, I changed out the under valve cover harness and the retainers that thread onto the injectors with new. Had solenoid go bad on #2 injector, replaced with reman. Ran a couple hundred hours and had faults for 1 & 6 injectors current below normal, having 10k hrs on machine, replaced both injectors. Ran a couple days and faults would intermittently come back for 1 & 6 current below Normal. Found injector harness had weak wires on both and replaced again. 3 times since then the orange wire for #6 which the schematic shows as “cyl 5 & 6 high” has broken. Have done the electronic timing calibration, visibly checked the damper which appears to be running true, have no vibration in the engine while running either with no load or full load. Will run about 150-200 hrs and breaks the wire again. I’ve changed harness twice and since then I’ve been splicing in ends until we can source the problem. Harness number is 425-0289, machine serial number is PAP00323 Have been working with TC at local cat dealer who has been in contact with Cat and they have no known failures of this harness. Seeing if anyone out in the world has had a similar experience and can throw some suggestions out. first two photos is what the wire looks like before you pull it in half like the last photo