Seems like they have an extra check in the end where they sometimes remove the image immediatly after its generated, for this one I can’t get it to stick but took a screenshot before it deleted the result:

https://media.utxo.nl/wp-content/uploads/nostr/6/2/6280891c890be4333ff6f8317a70db87ab1c7d1a08f7c4d6797d25bcd5f82f25.webp