/profile - Incorrect join date for a player

If you use "/profile Goblin_King96", it shows a join date after the network overhaul. This player was active before the overhaul months, if not over a year earlier, and I confirmed with them that the date was wrong. They have not changed their IGN, nor changed accounts. This could likely be verified by searching RPG server chat (they are mostly an RPG player) or possibly using /joindate in RPG, but I do not have access to either of these. They do have a nickname on RPG that I think may be admin set. I'm not sure if that's related in any way, though I don't see why it would be (when they first joined the server, they wouldn't have had a nickname)