When I embed a map into one of my articles, its background does not display. I am unsure if this is intended or not.
Add a background to a map Embed the map into an article View said article and notice the lack of a background for the map
Background image - in the current implementation only displays on the full page of the map - this doesn't mean it cannot be changed but it was never the case. I would suggest you open a feature request so we can address it :)