Problem with the Combat mechanics overhaul mod.
If you try to install 2 of these mods at the same time, placing the "territory fill" on the spot with ore removes it.

Are you using any of his other mods? Space Exploration will remove entities when tiles change for sure. Nothing I can do about that, as that's code he runs when tiles change. You can use the range of miners to get the edges without filling those spots and work your way into a patch.

I use 1 (2 of his mods)
Wall block splitters and CMO

but now... it is only worth your mod, because it is much more fun

Turns out this may not have been a scripting issue, but rather a collision change on landfill. New version fixes this with Space Exploration, and might for other mods that modify landfill, depending on load order.