There’s a famous chakirah in yeshivos if the kosher simanim are a cause or a sign; meaning if a cow is born without split hooves, is it still kosher? Do the 2 simanim cause the animal to be kosher, or are they merely signs of a kosher species, but whatever happens in individual animals is irrelevant.
The future taharah of the chazir implies that the simanim are causes, not signs.