>>45018128Bulbasaur also used Dig despite not being able to learn that move.
Bulbasaur never used Whirlwind anyway. It was just a dubbing error. Whirlwind is called "Blow Away" in Japanese, so Ash didn't command Bulbasaur to use Whirlwind, he just told it to blow the spores away. It wasn't the actual move, it was just an improvised move.