You don't run into that problem if you use Posers built in mt5, mt6, mc6 or other material files. I prefer them over mat pose files myself. I've had too many mat pose files not work properly for me anyway. First example that comes to mind are the mat pose files that came with AprilSH's Portia hair. I applied that commercial hair to V4 and neither the mat pose or fit pose files worked when I went to apply them.

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