A bad JVC adapter (ordered from Crutchfield) was the culprit. Once that was switched out (twice!!) it's working (knock on wood/so far). They blamed JVC for the whole affair (that the head units & adapters don't communicate with each other optimally). Of course the question is if JVC equipment is that bad why do they sell it? To their credit, they did keep trying until everything was resolved to my satisfaction.