Swapping the CC-M would obviously be high on my list. I can buy maybe one is bad, but multiple bad modules unless they've been abused would be very unusual! I've handled hundreds of CC-M modules over the years, and I've only had two that I remember that were genuinely bad, one was just a bad solder on an SMT component joint that was easily fixed, and the other one was simply in LaLa land, it seemed the microprocessor was off in space.
Obviously, my first inclination when I suspect a bad board or module is to take them to my test set and just individually test them.
