Good question! I've done lots of pre-orders on the SM Global shop and they've always had a lot of details for each album to the point where it was something I noticed. There was even like a gallery of pictures of what the album looked like and blurred out photobooklet previews underneath some of the albums I got on pre-order.

Whatever the reason, it's definitely unusual for them to do that in my opinion because I've been ordering from them for years.

Maybe it's just because there aren't as many details released to the public about that specific album yet?

Maybe one solution is that you can always cancel your pre-order. You can place your order to make sure you can get a copy, and once all the details are released you can decide if you want it or not and cancel the order if you don't like the format etc.