I don't have an answer, but I can verify that V4 has all sorts of weeird things going on when you try to make custom morphs. I have worked a long time on some leg morphs using magnets to do the shaping. Everything seems to save as a morph just fine, but when you bend the leg all sorts of odd deformations occur. I suspect it may have to do with those blessed magnets that Daz stuck all over her body because they couldn't be bothered to model her properly, but that is an opinion, nothing I've been able to verify.

If anyone ever gets this sorted, please reply. I'd like to know the answer, too.