I would have assumed, that in the case of changes & bugfixes, the original version at least has to stay "the official" one, the one others play & rate within the rating period. But as it is written in that rule (if I understand correctly, I am no native speaker), this is not the case. You can present your changed & bugfixed version on the big stage, and just have to make sure to keep your original version somewhere in the basement, so to speak.
Ah, my interpretation is the opposite as yours! (I am no English native speaker either, by the way. ;p)
I guess this is up to the Mini Jam bosses to enlighten us up as to how the rules should be read into!