I can't count the number of times I have been misled by something like this. For example, you change one cable to fix a problem in another and while you are changing it, you accidentally bump the other one, fixing a bad ground connection that was actually causing the problem. Result: You incorrectly conclude that the cable you changed was the problem, when it was actually the cable you bumped. I'm not saying that is what happened in your case, just that I have experienced similar things more than once. Usually it happens to me when I am trying to diagnose something much more complex and I end up wasting days pursuing a phantom.