As others have stated it has always been like this, but irregardless the falloff zones should mirror over correctly. I have manually altered those rotations values to reflect true symmetry and the falloff zones go wonky needing maual correcting. When I did this I really didn't see much difference from the Poser symmetry and my manual edited symmetry for my rig...it still seemed to act the same. (ie; it will always follow the falloff zones)

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