The "marking" in this case is not inherent in the cards; but is rather a combination of an assymetry in the cards, and the dealer rotating a non-random subset of the cards (thereby turning the assymetry into a "marking").

Further, in order for a marking to count, it has to "tends to deceive the public or tends to alter the normal random selection of characteristics or the normal chance of the game which could determine or alter the result of the game." If the only mistake that the dealer makes is some form of an information leak, and no one modifies their behavior based on the information being leaked, then this condition would not be met.

If, instead, the dealers mistake changed the odds of the game regardless of if the player acted on it, the this clause would be invoked. Indeed, this is likely the intended case of this clause, as the alternative is that the house can cheat.