Sorry, I'm confused now. What kind of trouble is it that Antonia's rig has and other figure's don't? Do other figures show asymmetry in the zero pose or not?

By the way, I was wrong earlier. It's not just a uniform shift applied to the whole figure. I exported the figure in the zero pose as an object file, and I see that the centerline is still at x = 0, but the overall symmetry is broken.

-- I'm not mad at you, just Westphalian.