Perhaps few reasons...

Around that time (Nov '23 - Jan '24):

 nostr:npub1jfujw6llhq7wuvu5detycdsq5v5yqf56sgrdq8wlgrryx2a2p09svwm0gx introduced ~territories
 nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm went behind invites
 nostr:npub1hcwcj72tlyk7thtyc8nq763vwrq5p2avnyeyrrlwxrzuvdl7j3usj4h9rq left the USA