I don't know if there's an answer to this,It might just be a limitation of the model.
I've been trying to pose M4 with his skeleton and muscle maps and transparencies to use as references for a project. I'm pretty new to Poser so bear with me.
First off and this may be of some use to other newbies, it took me quite a while to work out how to get the M4 skeleton to move in unison with Micheal 4. Move Michael and the skeleton stayed where it was or vice versa. No amount of 'Parenting' Setting or changing figure seemed to solve the problem. I may well not have been doing this correctly or going down the wrong route entirely but in the end all I manage by this method was to get the two figures to rotate in unison along x y or z  axis and that was it.

Solution - load Michael, load M4 Skeleton, choose Conform to from the Figure menu (which for a moment makes the skeleton' knees stick out and you think you're on the wrong track) Follow this with Zero Figure, again from the Figure menu and you're back on track  and you can go ahead and load up muscle maps and a transparency for the muscles and there's your skeleton visible through the muscles and it all moves as one. So far so good.

There are some limitations to the poses. One is quite understandable. I imagine  a fully articulated vertebra by vertebra spine wasn't really feasible on this sort of model so bend him too far and Michael gets breaks in his spine. I can live with that,he still looks pretty good,very usable for all sorts,great for working out poses and sketching from for starters and for final images.

After all that waffle ,here's my question. When I try to move the lower jaw, regardless of whether I move michael's jaw or the skeleton's jaw,the skeleton's jaw always moves and Michael's mouth remains resolutely shut. Is there a solution to this or is it just a limitation of the model or a bug even? I can live with it,just wondering if there's a solution.There may be a few other little quirks like this that I haven't found yet,perhaps in facial morphs as a whole and if there's a solution perhaps it applies to all.
Any thoughts much appreciated.