Did they all come from a seed packet? Or did you save seeds from one you bought or grew?
If purchased seed, well, mistakes happen. It will be edible; other qualities may vary. It could still change color- pumpkins change late.
When you save seeds of any squash, there is potential for crosspollination. It depends on just which other squash plants were in the 'neighborhood. where the first squash grew. It won't make any squash inedible, it may affect color, shape flavor.
