Update: He just got perma banned for literally NO REASON

BdawgTheSlaya That is all we did, so
I downloaded a menu from nexus, put it in the files, gave him co-host for it in a private game and he was banned while I wasn't; He has not touched anything apart from the vanilla game (with the exception of plutonium ofc)

incelfreak Nope, he most likely has to ride it out, it's a 7 day ban anyways. All I can say to anyone that stumbles on this thread is that it's best to play vanilla, even solo/private, as the anti-cheat seems rather fickle (which is good in an arms race sense, no criticisms on that.)

BdawgTheSlaya just did some more research, wasn't aware that mod menus were ban risks even in private games, as long as it's online (assumed it was allowed, privately I mean, due to the mods button on the menu); That's probably why, though, he wasn't the one who got it, and was instead me, however I am left untouched (we played together).

^^ So far, he has only played on his own or with me; Not sure why or how he got banned but we feel it's necessary to make a post about it in case it's a false positive that will cause more issues down the line