Bill,
Perhaps a bad bond was part of the problem but, my point is I feel that it is better to secure that GEC where it enters the panel. Or, on the other hand, if you can't use a NMC connector because it isn't listed then it should enter the panel by some sort of raceway, either PVC or EMT (properly bonded of course) but by no means should it be allowed to "float" inside of that 1/4" or 5/16" hole unsecured where arcing could ever become a problem.
