I can't tell you how many times I've encountered this in the past. The frame bonding to the neutral that used to be allowed was always the culprit. Since the neutral isn't really needed in a typical range, oven or cook top for anything but the lights, clock, etc., the leaks were always strange voltages.
Since a cook top rarely has any 120 volt requirements, I often wonder why there is a need for a neutral to be provided at all.
My question here is where was that stray voltage to ground coming from? A failing element? That is the only thing that I can think of, especially in such an old cook top.
