Ok, so I lied, I was going to look today and it didn't take me nearly as long as I thought it would as most of the prescripted_counties folders added by mods were zipped up. They didn't exist in the few that remained (mods that add prescripted empires that I modify to my tastes and then remove the mod from the playlist) so I have no clue where they are coming from.

Is the nation named different in each save? Or did it only appear in 1 game? If it's the former, then it was probably pre-FTL humans in the Sol system that gained FTL tech.

If the former, do you have a mod that forces the Commonwealth of Man to spawn or perhaps just a forced to spawn copy of the COM? The Lost Colony origin will force spawn another empire of the same species. Interestingly, if you mod the game to always force spawn the UNE and COM, the UNE will not be considered the the counterpart and you'll have a 3rd Human empire with a generic name in a random system and not the Sol system.

I guess the most important question I have for you is "does the League of Human Colonies contain the Sol system?" Because if it does, it's likely pre-FTL and if it doesn't, it's probably COM related.

I always play Humans on Earth in the Sol System, so forced spawn CoM happens. They are always named League of Human Colonies with the name showing up in the save file as "NAME_League_of_Human_Colonies". I looked int the save files for a few starts to see if I can find any clues to figuring it out. It's got the flags "human_3" "human_faction" "distant_origin_empire" and "nontemplate_country" which is making me thing Distant Origin is the culprit. The other constant is that they always spawn in 40 Eridani. When I get home from work today I'm planning to go through and look through Distant Origin to see if I can find anything related to them.

Found it. It's actually Forward Earth that is doing it, so going to make some adjustments to the files. I don't mind the League, the problem is that they are a FTL nation close to me, and I don't like that.