I believe Ivey really did notice this irregularity and took advantage of it.

With that said, the irregularity in the cards is the casino's fault, and if they provide a keen-observing Ivey the edge, then that's part of the game. That's not cheating.

Cheating is using some sort of device to aid your play, or to have a partner at the casino staff helping you gain an unfair edge. If you notice something that allows you to swing the odds in your favor, and take advantage of it while following all of the game rules, you are not cheating.

Crockfords needs to pay up.