First of all, amazing mod !
If planet or space-location define starmap_icons instead of starmap_icon, sprite was not build and so not show up
Nothing important just a suggestion !
A mod can use vp_override_planet_sprite("fulgora", "mod-name/banana.png", 320) to set a specific sprite for a planet/space-location if it doesn't define starmap_icon. (Checking if this mod is enabled first to avoid errors of course)