I have a game with about 19h, using Xander Mods from Therax fork, and just added RSO, but once I open my save file, I quickly realize it has created huge patches right in my starting area. Is this an expected behavior? When I remove the mod and load the game again (I didn't save it with the mod, it is still the load from before adding the mod), the huge new patches are gone.

I will do a backup in this save so I can make new tests if required.

It looks like starting area creation check failed to figure out you are already in game from some time. I might have broken it in recent changes. I can take a look and try to fix it but adding RSO to a running game is not fully supported. If you didn't explore far it should be ok, areas you already explored will not be redone unless you regenerate ores with command.
New version up and it shouldn't spawn new starting area when added to save.

Wow, awesome, thanks for such a quick reply and fix, gonna try it out.

Just tested and the problem was solved, thanks.
Oh, by the way, even though the game is already 19h, since I am using Xander Mods, I am still in the starting area lol, Xander Mods make the game start waaay longer.