NixOS GNOME shutdown screen always warns of other users that don't exist

I have a NixOS 20.03 VM running GNOME. Whenever I go to shut it down it always warns of other user sessions (all my user account) logged in to the system. Having a warning for this is great, except that I’m not logged in twice! I don’t even have SSH enabled.

What’s up with that? Why is GNOME warning me about ghost users?