Quote - I'm not sure where the additional distortion comes from, but I think that it's something to do with the fact that when the joint magnets act on the BentKneeCorrectionMorphFromHexagon morph part of the NewBentKneeCorrectionOnlyMorph morph, they are acting, to some extent, a second time.

As the magnets will have been influencing the shape of the knee when the bent knee was exported, it seems to me that when you apply the bent knee morph at -1.0, that influence should be exactly cancelled out. So thinking about it, I don't see how they could be acting a second time. One point to keep in mind, the magnets don't know that the knee has been morphed. They will be acting on the unmorphed shape, though I would be surprised if that fact could account for the amount of distortion seen in your image.

[edit]
What does it look like if you now delete the magnets?