BuddyPress.org

@jluisrioja
You can use the following code inside the child theme, it will add a timestamp for all users
remove code once all member starts displaying in your member list.

function buddypress_add_last_activity() {
  $members =  get_users( 'fields=ID' );
  foreach ( $members as $user_id ) {
        bp_update_user_last_activity( $user_id, bp_core_current_time() );
  }

}
add_action('bp_init', 'buddypress_add_last_activity' );

Thank you, Varun.
The whole issue about the members count is very confusing.
Here is what I have in the members admin section:
All (1,325) | Administrator (3) | Contributor (1,313) | Keymaster (3) | Participant (1,253) | Pending (0)
See how the numbers don’t add together to the “All” number.
After running your code, in the front end “users” section I have now:
Viewing 1 – 20 of 1,735 active members
But when I sort the members alphabetically I get 985 members.
Here is the link to the website: https://onegative.org/members/

not a good idea