By the way, you just made me realize the practicality of a subtle one-way back for magic... I had never thought of it before. And by mixed alignment, you mean some faces have the weathering reversed?
The backs are done in an identical, asymmetrical pattern. Granted.
Most decks done with an asymmetrical pattern have all of the faces oriented in alignment with the backs. This way, say for example you're holding the deck vertically in your hand - when all the backs are oriented right-side-up, the fronts will also be oriented right-side-up. Some cards have directional indicators built into their pip pattern - the ones that don't you can usually tell by the nearly-universal off-center cut. (The level of precision to print all the faces on the exact same spots as all the backs is extremely difficult, so when a deck is center-cut to the back pattern, the faces will usually end up slightly off-center.) This means that a sharp observer might notice the card faces are all oriented the same way with at most just the chosen card oriented the opposing way, from which he or she might deduce that you're using a one-way deck.
With the Series 1800 decks, assuming you're holding the deck the same way as before, when all the backs are oriented right-side-up, only about half of the faces will be right-side-up, leaving the rest turned upside-down. This makes it harder to tell from the faces if the deck indeed has a one-way pattern. The mix appears to be fairly random, not following a pattern - my guess would be that the card sheet back was printed with the card backs oriented one way on the left and the opposing way on the right rather than the same way for the entire back of the sheet.
A subtle one-way deck can be a powerful and useful tool for magicians to use, and makes for a nice backup in case you screw up a trick, giving you a way to still find the card (unless they're dropped or shuffled incorrectly).
A partial listing of all known recent-issue subtle one-way deck designs:
Bicycle Karnival - from original to Dead Eyes
Bicycle Guardians
Bicycle Series 1800
Phoenix "Phoenix Back", regular and marked decks, all formats.
Bicycle Gargoyles (and pretty much all the other Diavoli decks other than the Bikes in colored Rider Backs).
Split Spades Bee and Tally-Ho decks - I suspect it was a printing accident since it was removed for the SS Lions.
ANY stripper deck, except for ones that are professionally cut with an extremely shallow edge. I have a few of these shallow-cut decks, and they're nigh impossible to detect, good enough to fool a magician.
I'm sure there's more but my brain is hanging up the "CLOSED" sign for the night...
