1. Phorge at 8a3b70aa7d4c3376dabf5dfd5d3a0df68998711c, PHP 8.3.6
2. Go to http://phorge.localhost/badges/recipients/1/
3. Click + Add Recipients button
4. In the dialog, enter no username and click Add Recipients button. Dialog vanishes.
5. Go back to http://phorge.localhost/badges/view/1/ and see the line username awarded this badge to recipients: .

List of recipients is literally empty because that faulty transaction passed. PhabricatorBadgesBadgeAwardTransaction.php has a validateTransactions() method. No idea if that's ever called somehow. Seems not in this case.