Thanks for pointing this out. The numbers are different because on the user list page tally, we exclude users that are in the database but are not active participants in your community. This includes:
- inactive
- staged
- silenced
- unapproved
anonymous mode
This more accurately reflects the total number of members in your community, so will update the about page to match the number on the user list.
On the admin user list and in reports you will still be able to see all users.