This seems to happen sometimes with Big Box tools, brand new out of the box: the two battery toolset will have cells from different lots (presumably:) one known

This seems to happen sometimes with Big Box tools, brand new out of the box: the two battery toolset will have cells from different lots (presumably:) one known to work, the other questionable... you did still get two batteries for those tools, but it sure does seem like the same one is always charging. I've had this happen both from Amazon and HD/L.