"What happens is that if you're using a Michael 4, then you import another Michael 4, or any part of him (i.e. head), then save the scene out to the usual pz3, there's a chance he will lose some of his morphs. This also happens if you save him to the figure library when another Michael 4 or any other parts of Michael 4 are parented to him."

 

I had the same experience. It happened after I installed the DSON importer for Poser. I deinstalled it and afterwards the morphs were saved as usual. Recently I tried DSON again but with the most recent version of the DSON importer and the problem did not appear again.