Hello Boyer,
I should have included the images before. By red cupid deck I meant the classic red deck from Bicycle. Here are the images of the card and the back in the original placement from the deck.
Boyer is my family name. Call me Don!
The confusion stems from the name you gave the design. The "classic" Bicycle back, used in Bicycle Standard decks today, is called the Rider Back, because of the cherubs riding bicycles in the two circles. There's another, totally different back that's known as the Cupid Back, a very popular model and often re-released around Valentine's Day (February 14).
It does look like you ended up with this from a different deck. I'm not certain what's in my pack of this deck that I have opened, but it's not unheard of for an "odd card" to end up in the deck by design. They get used by magicians for performing certain magic tricks. I have a deck in my bag right now, Bicycle Grimoire by 9780 Design, which comes with a "double backer" card - two backs, no face. The backs are different from each other - one is the standard back for this deck, while the other is a red Bicycle Maiden Back. They're often referred to as 'gaff cards."
I'd have to check, but it's possible that this is meant as a gaff card for this deck, especially as Bicycle Standard decks are made on a different printing press, used for high-volume print runs of common decks. A good determinant would also be the total number of cards in the box - USPC prints poker-sized decks almost invariably of 56 cards - 52 playing cards, two jokers and two extras, generally used as either gaff cards or advertising cards. If your deck has 57, then it's likely that the extra card in your deck somehow got mis-sorted into your pack.