I got a replacement joint account card, which activated successfully, but it isn’t allowing me to add to Apple Pay. For some reason it keeps reverting to trying to add my (existing) single account card.
I’ve raised this with in-app chat but no response.
Have you tried to add directly via Wallet instead of in-app?
Huh, I didn’t even know that was a thing! That seemed to do it! It was pre-filled with my old joint card details, so I did Add New and it worked. Clearly something got a bit confused along the way.