During the brief span between updates 1.1.0 and 1.1.1 to Sword/Shield, using Fairy Lock with animations on caused the game to crash. As this predates Isle of Armor and the reintroduction of Klefki to the game, the only legal way it was even possible to use Fairy Lock during that time period was by randomly calling it with Metronome, which for some reason it hadn't been excluded from.
See https://twitter.com/DaWoblefet/status/1216834809227399169 for a sample case.
