Scott made up the lore as he went; the first two games already contradicted eachother.
My theory is that fnaf never had such a thing as a constent cannon lore; even at the very beginning Scott was already rewriting it with each new game.
The earliest example I could find of it is this: in fnaf 1, the posters which we first found out about the MCI from say it happened at Freddy Fazbear's Pizza and that the bodies were put shoved inside the animatronics there which caused them to smell.
In fnaf 2, we found out from phone guy that the old animatronics were brought from the "old location" and that they already had the kids bodies inside of them at that point (because he complained about their smell); so far so good. But then in another phone call with him in the same game we find out that the previous location was called Fredbear's Family Diner, which already makes no sense with the posters from FNAF 1.
And then, as the last nail in the coffin, in the ending of fnaf 2 we find out that Freddy Fazbear's Pizza is the new fnaf 2 location which contradicts the fnaf 1 posters even further.
I can already see some die-hard fnaf lore fans try to explain this contradiction with some insane theory about animatronics being moved back and forth between locations like they always did with any contradiction that new fnaf games had with previous ones.
After nearly 12 years of riddles and theories it's time we finally come to terms with the truth about fnaf lore and move on: FNAF LORE WAS NEVER CONSISTENT. I know this is unpleasant to hear, but as I just showed we could see signs of this early on and it olnly got worse as it went. I myself used to love fnaf lore and watch theory videos for hours, but I can no longer deny the facts: the franchise never had a consistent lore; it was being improvised and redconned by Scott with each new game and because of that, there's no use in trying to make sense of it.