Looks like it's a glitch on the B&N site. The sale is SUPPOSED to be Buy One, Get the Second for 50% off (so basically 25% off), but the site is treating the sale as BOGO. Same thing for strategy board games like Catan, Pandemic, Ticket to Ride, and Unlock! products.
Almost all the X-Wing stuff is sold out online, so I went to the store down the street. The sale was all screwed up, as some of the items didn't recognize the sale at all. It's as if the store marked all the games with the name "Star Wars" as part of the sale, but not all of the X-Wing product have "Star Wars" in their names in the computer system.
The store manager was called over, and he verified that the sale was not BOGO, so I told him that I'd pass on my purchase. He went ahead and manually discounted everything to BOGO for me because it is so royally screwed up. Hats off to him.
I went onto the site and bought all the other games I wanted that are incorrectly discounted before B&N fixes the glitch.
EDIT: They fixed the glitch.