Oh; darn, now I need to know where they get their stats from.

Well I'll just say my dumb idea. It might not be this, but I observed that fedidb would double count instances for kbin. It was doing this for a while with fedia.io where it also listed www.fedia.io under it with the exact same MAU / user count. Not a big problem, but as I was checking in each day I noticed it suddenly added kbin.social under another subdomain as well, doubling all of its counts. Then, eventually, both dupes were removed. So my idea was maybe this was during that time when suddenly the largest instance was being double counted. Maybe not, just wanted to mention that I had seen that happen

Edit: I guess they get users themselves, so unless they had the same glitch, it was likely unrelated, my bad