I remember when we had a fault on our RR Trent Airbus 330. The EGT was causing erroneous indications. We traced the fault to a chafed wire on the egt harness onto the CNA. It was the green one and I can't remember it that's alumel or chromel.
An easy repair would be to cut at the chafe put in in line splice and heatshrink sleeve, a permanent repair as per Airbus chapt 20. However our RR wiring practices manual expressly prohibited in line spice repair on EGT harnesses. We put in a query with our technical service boffins and we were advised to replace the entire harness. A big job on a Trent!
So what would have taken 20mins to fix as per Airbus, took an entire day because of Rolls Royce.