Apple Pay fails on Apple Watch Ultra2 worth WatchOS 11, paired to iPhone 15 Pro

Purchased a new Apple Watch Ultra2 with WatchOS 11. Installation forced my iPhone 15 Pro to update to IOS 18.0. Now Apple Pay purchases with Watch fail. They seem to work, but moments later come back with a “declined” message.

Chase Fraud: We declined $XX.XX with card ending XXXX at KELLEY ORCHARDS.

Was this you? Reply YES or NO.

If yes, you will not be charged unless the purchase is attempted again. If no, we will close your current card and send you a new one that you should receive in 5 to 7 business days. Msg & data rates may apply.

I replied YES and tried again, receiving the same message. It just won’t go through. The transaction obviously gets to the credit card vendor, but the handshake appears to fail. I have tried deleting the card and adding it back on the watch to no avail. Anyone have any ideas?