At the table, they didn't know yet that it was a bluff. He folded, they revealed that she had nothing by saying "Bluff", that's all. No "bluff card" in play.
That said, Finns and facial expressions...
I wondered however if she had kept her cool had it been her own money at stake.
Watch it again. There is a bluff card. This is a gameshow style poker. It uses special rules which make no sense to the normal poker player.
I think because they are making a tv show they use a bunch of prop cards like this bluff card but there are other types of cards that also do weird things and make no sense. Just like making the guy go to the cage because he lost the hand. Just weird stuff for a game of poker.
Here is the timestamp of the bluff card.
https://youtu.be/jCO0c7fJ1pQ?t=265you can clearly see it being flipped after she lays it down (instead of laying her hand so that she doesnt have to show what cards she had, but then she shows them anyways.)