Here's a pic of antonia in the same pose, with non uniform Y scaling on her nec. Same thing happens that Happens on Kids, M3, M4, jessi, James, G2 figures, Apollo and every other figure I tried.

This is a screenshot of Antonia in Poser Pro 2010.
neck and head nodding forward, Y scale at around 150%

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Renderosity Store  Personal nick: Conniekat8
Hi, my name is "No, Bad Kitteh, NOO", what's yours?