Max Balloon also prevents damage to the bench

I was attacking a Flying Pikachu VMAX that used Max Balloon the previous turn with Amazing Rare Raikou. I hit the Pikachu for 0 damage, that's ok, but also hit a Bidoof in the bench for 0 damage. There was no Manaphy in play and no other interactions.

The text for Max Balloon states "During your opponent's next turn, prevent all damage done to THIS Pokémon by attacks from Basic Pokémon." so the Bidoof should have been hit for 120 damage.