Sorry to report this (but nobody said it would be perfect). If you open the P4 Nude (at least) that has had the thighs scaled less than 100% in Y (I always scale 'em down, they look too long to me) and turn off inverse kinematics, the knee joint breaks, as shown. A workaround is scale them back to 100%, turn off IK, then rescale them. You still get a movement, but it doesn't beak the joint. Anybody know how to make the default so IK is off? I seldom ever use it anyway.