Why does a card from the new set count for a deck highlight mission of an old set?

TheDragonNoodle

I just opened a pack from Wisdom of Sea and Sky, and got the 2 star Mismagius ex (the kind with the sparkly white background). But it completed the "highlight card for mismagius ex deck" from the space-time smackdown expansion. Is this a bug or error of some kind?

Justerfrog5557

The cards are functionally identical. The game isn't going to stop you from getting a decklist with the card just because it looks different.