Comment by pauloday

It's not that the cards were marked because they were asymmetrical, it was the combination of the asymmetry and Sun manipulating them that caused them to be marked. So other games with those cards are fine as long as none of the players were manipulating the game so that asymmetry gave them an advantage. The player didn't bring the cards, but they did purposefully manipulate them to effectively play a game with marked cards, and that's why the game wasn't legit.