The Overload permasupport no longer functions how it is worded

In the Tour de Ravnica event, the fourth encounter is Nivix, Aerie of the Firemind. The permasupport named "Overload" reads: Whenever a player casts a spell, for each spell in their graveyard, the opponent's planeswalker takes 1 damage.". This used to work fine, but this is the second iteration in a row where the support only does 1 damage, regardless of how many spell cards are in either graveyard.