So, we know what it's doing, but is that right? This remains the question.

Like many others, my vote is no; I think you are correct and that eights-up should lose to sixes-up. Like the anon reply to your comment, I believe Robert's Rules imply that the mechanism for ranking two-pair hands in Razz is no different than in other poker games, save that the lower hand wins. In any case, it looks like this issue is being looked at/resolved already, so...yeah. :)