Herdier and Victini are listed as receiving the move. Moreover, they are listed as the only Pokémon to receive the move.
Edit: I set the tier threshold to NFE (if that makes a difference), and I now realize that the problem isn't limited to Volt Switch. For instance, Sucker Punch is listed as being learned by Emboar and Serperior, Hidden Power by literally five Pokémon, and Leech Seed by Liepard.
Wonder what's up.