Not the person you're replying to, but it affects both the boarding pass in the app and, by extension, the one in Apple Wallet. That said, when you go to board using your old pass, the machine at the gate will print out your new seat assignment, just as if you were upgraded, so I don't see it as an actual issue. Maybe in an ideal world the boarding pass would update, but there are certainly much larger IT issues that DL should be focusing on.