@nova
Oh interesting! Thank you for bringing it to my attention.
In my case the missing 2,600 followers are in limbo as they are no longer at the old account either.
My idea at first was that one cause for this could be short-time users of Mastodon who just tried out the service 1-2 times and then haven't logged in again, thus not triggering the re-follow. Not sure if this is a realistic theory.
In my case there is the added complexity of moving to an Akkoma instance, so I'm guessing there are issues with this as well.
I do now have examples of people who are listed in my followers list not actually following me (they have the "Withdraw follow request" button). I also have people who are following me but are not listed in my profile as followers 😂
@shanselman