Hmm ok, that makes sense. I know the last 4 are different because the digital card in Apple Pay gets a new 16 digit card number, so that part is definitely right. I'm glad to hear of someone else getting a different expiration date exactly three years past their actual date, as that was what my situation was.
As I mentioned, we stopped the transaction because we didn't know if that would be an issue, but it could have gone through. I should have my new CC tonight, so I'll register it with Apple Pay and perhaps go back to a different merchant to see if it now works. I also restored my phone yesterday as brand new to rule out any software bugs.
I can't figure out why you would stop the transaction. Why not just let it go through and see what happens?