[Spook]

I 'think' it was because the second player who looked at their cards and folded said something.

there was no other mixup with the cards. (there was a card dealt ambiguosly a few hours previous, and it was a misdeal, but that was a good dealer who insta stopped the game.)

edit: and even if there was another mistake, the dealer never stopped the game until after three people had acted.