When in a Shop Pay checkout context and the customer is logged in, if you update the address with the useApplyShippingAddressChange hook, the selected saved address is deselected, and there is no option to edit the new address.
So there’s no way to checkout with a temporary address without adding it to the list of saved addresses for the customer
And we have no way to access or update those saved addresses, AFAIK since they are on the Shop Pay customer account.
This is causing issues for apps that automatically update the address in some way, eg. zip code, since it makes the Shop Pay checkout unusable. I think previously you could still enter a manual address, and that’s why this issue didn’t happen in the past. It works this way in a regular checkout.