Cornerstone Ogerpon took damage, but according to the battle log attacking pokemon had an ability??

Okay so I'm kinda new and not really sure what happened or where to put this. I was playing in a ranked battle and had my Cornerstone Ogerpon Ex in the active spot, who's ability shields it from any damage done by a pokemon with an ability. My opponent's active pokemon did not have a ability (Hop's Zacian Ex), but for some reason was doing more damage than it should have (30 from the attack, additional 30 from Hop's Choice Band) instead of doing 60 damage it was doing 90. So i checked the battle log to see if i missed an item or something, and it said that the Zacian had an ability that was letting it do 30 extra damage? I removed the player's name just since it wasn't relevant, but this is the breakdown of what the logs were saying were happening.

[Player]'s Hop's Zacian ex used Insta-Strike on VenoNat543’s Cornerstone Mask Ogerpon ex for 90 damage.

• Damage breakdown:
  • Base damage: 30 damage
  • (Ability) Extra Helpings: 30 damage
  • (Pokémon Tool) Hop's Choice Band: 30 damage
  • Total damage: 90 damage

I'm not sure if I'm misunderstanding the rules of how Ogerpon's ability worked or? Just genuinely confused on where the extra damage was coming from!