This event has been made available for players via local wireless connection during the 2022 World Championship in London.
Thanks to @zaksabeast for this contribution!
The developers of this event incorrectly made the wonder card be set to random gender (Male or Female). However, the Sinistea will be correctly genderless when received in-game.
As of LGPE, wonder cards are no longer stored in saves. As such, players will not be able to inject this wonder card into their save using PKHeX, for the purposes of redeeming it in-game.
Format Ver.2.1.2-12, Post Updated Date:20220818_2116