Not really. What happened is that the hen accidentally released two yolks at the same time instead of the normal one. If she had released two a bit apart she might have actually laid two eggs that day. It happens.
As long as this kind of thing is infrequent, well, I figure we are all allowed an occasional oops every now and then. If it becomes a regular occurrence then there is probably something wrong with the hen. That kind of stuff is more common when a pullet is just starting to lay but it can happen to any of them. Since that is the first you've seen, don't worry about it.
As to the crack, that sometimes happens too. What I think might have happened there is that the hen only makes a certain amount of shell material in a day. Since that egg is so big, that shell material had to cover a lot more surface area than usual, which made it fairly thin. Since it was thin it was easy to crack. Again, I would not worry about it unless cracks become common.
