My 1998 Nordica "next" boots never gave me this problem, and I basically just bought them at a sporting goods store. This time I go to a locally reknown bootfitter and my toenails fall off. Go figure.
In all fairness though, my second time out in the boots I really concentrated on staying forward in my stance and the toes did a little better, which tells me that skiing in the backseat was partly to blame causing my feet and toes to slide forward.