So I'm creating a moon in my custom system, its the default template i want with maybe a few modifications - radius 250, mass 5000. However when I change anything in the terrain or gameplay, it bugs out and becomes radius 1000 - which obviously I don't want. Is this a known bug, and if so, is there a fix?
In your custom system, were you adding a moon to orbit a planet? If so, what kind of planet was it orbiting?