Mike,
I think it was changed at 5.1.2 and seemed to relate to a change with "Longer" exp - I've never been able to get a straight answer as to whether it was deliberate or a by product !! I did a quick search and found this
forum search I also recall a kodak person pointing out that they had changed the setup but I don't remember why, this also talks of the same issue
second archive link
I'm not sure if its good or bad - at least you can clean without mains power which is great for location shooters !
atb
Chris