I created a multi body to simulate an injection mold tool so I can think about fillets and radii from the tool perspective. I used part painted to color the cavity green. I then did a multi body publish and created an assembly. I then decided to return the cavity to the default gray color. The linked models such are not updating - they are staying green. I've tried using the update tools and check the multi body publish dialogue which shows all links are up to date. Is this a bug or am I missing a step?
I believe that when a Part Copy is created, it will copy the face colors if the setting (defaults on) is set, but it is not associative to the parent so changing them after the part copy has been established has no effect.
Ken Production: SE 2019 MP4, Testing: SE 2020 http://Grundey.blogspot.com
Perhaps only form is updated in a multi-body update after publishing. That might make sense I think. You may not want color changes to flow through and mess up your color scheme in the published parts.