I’m just working this issue with Apple support. This maybe a work around, possible. I’m waiting for a call back….
Go into “All Watches”and click the “i” in the watch app.
Unpair Apple Watch
This removes all data. (Something gets stuck in there)Don’t worry you will get it back.
when it comes back you want no data. Thing will be blank when it all comes back.
Add the card on the watch like you normally add a card.
Unpair the watch again
when it comes back pick a backup file you’ll see. Look closely at the dates.
Select the second oldest if it’s a recent backup file.
have a look at the wallet it should be now be there. Hopefully.
It’s a long painful process…