Hi there,

it might be the case that players have the mod AbandondedRuins_updated_fork installed which handles spawning ruins on surfaces, like planets. It might happen that players have suddenly ruins spawned on your surface which might not what you wish to happen.

If you don't want this, there is an easy fix available:

if remote.interfaces["AbandonedRuins"] then
    remote.call("AbandondedRuins", "exclude_surface", "<your-underground-surface-name>")
end

Replace <your-underground-surface-name> with your mod's surface name and no ruin will spawn underground anymore.

PS: I can see your mod supports multiple underground "surfaces".

Can you give me a map seed and a position of such a ruin?

It was my lucky guess that ruins might spawn on your mod's surfaces as the framework is generic. My mod makes no checks when the player is on a surface. Hidden/"internal" surfaces like e.g. NiceFill uses are always excluded. So if you want no ruin is being spawned on your underground surfaces, then please add a similar code to your control.lua.