It seems I must be certain that I’m dealing with the absolute original rather than just using a random copy to make changes. Yes? Still, why didn’t the exploded item with a custom color assignment not read when place in render?
No
You can Insert and Explode any instance.
Modify the parts, and make a block WITH THE SAME NAME AS THE ORIGINAL TO OVERWRITE IT.
Rendered display and renderings use MATERIAL assignments, not layer COLOR assignments.
OH, Now it’s more clear. so "color’ is only valid in the other modes. Material must be used in the Render mode.
Bingo
Bingo and Happy Thanksgiving!