Renderotica

Just off the top of my head and without any more information.

I can think of two issues that could cause a mis match.

1. Texture on the figure includes displacement or normal maps and the additional maps and settings weren't copied over by the Mat Copy script

2. There is a shader mismatch that isn't being picked up and copied over. As an example if the Figure textures are using PBRSkin shader and GP is using Iray Uber then you would end up with the textures not matching until you change the shader base on GP to PBRSkin. 

It could also just be down to how GP copies the Materials with the script, while most of the time it pulling and copying the material from the torso/body maps doesn't cause any issues. There are going to be some instances where just doing this means things might not line up right, an example I can think of is if the torso has a lot of detail like birthmarks or freckles with the way the Material Copy Script works by pulling the texture maps from the torso and applying it to the GP surface, in this case there is good chances that it is going to line up a birthmark of freckle along the seam of where GP and G8F torso meet and it might look off. Also there are sometimes variations in skin coloration in some maps so depending on where the script pulls from and where it places the map on GP itself it can sometimes cause a skin texture mismatch just due to variation in the skin tone of the particular character used.  

Hmm with it being Teen Josie 8 maps, I can't test it to see if I could replicate it (I don't have any of the Teen or Younger Characters) it could be Daz sabotaging the map somehow so it won't work with Adult figures and grafts, but even in the event that isn't the problem, if it were to turn out to be something that would need a custom fix, likely you aren't going to get a lot of help/a fix because of it being the Teen Josie 8 textures. My suggestion would be using a different texture as a starting point. 

I suspect what you were seeing is a common issue with grafts. Occasionally they get glitched and separate from the parent object at the seams. This happens to me a lot in complex scenes where I'm applying a lot of different poses, eventually Studio goes "wtf I give up" and grafts get screwy.

If this was the issue you were seeing, simply save the scene and reload it, and that usually resets the seams to connect.

If that doesn't fix it, only thing I can thing of is if you accidentally (or purposely) set the parent object as a collision object.
A graft cannot collide with its parent object or it will separate from the parent at the seam.

If it's neither of those, I have no idea :)

Originally Posted by: BrotherHades

If it is the graft separating at the seams issue, it can even be caused by what tool your have selected. Things like Mesh Grabber, Joint Editor, Geometry Editor, etc if selected will all cause grafts to separate from the figure. Usually if they are the problem it is as easy as picking a different tool like the Node Selection tool

This too :)