Amazon should correct the title of the listing.
But this seems like odd marketing. If I had a Blu Ray player, why would I want both a regular DVD and a Blu Ray version? Those who don't have Blu-Ray players certainly don't want both versions. I can't imagine a common scenario where someone would want to purchase both. I would think almost all consumers would want one or the other for a lower price than the two disc set.
I certainly don't want to have to buy a Blu Ray DVD that I will never watch in order to get the regular DVD.