Katsiki, that is an intriguing observation.
We're at ~7,300 users right now, but the forum set its
all time record for connected users just today at 8,820.
That would be consistent with either a DDoS attack or a sudden spike in traffic causing the general forum lag (it's been essentially unusable for me).
Has MMM gotten any recent extremely large press/online coverage?
It is also possible something with the overload of the server is causing it to lose track or double/triple count unregistered users, which would mean the extremely high guest counts would be an effect rather than a cause of the problem.