Storefront GraphQL API cartBuyerIdentityUpdate mutation does not seem to be working correctly

[gb-bigfish]

I call the cartBuyerIdentityUpdate mutation on the Storefront GraphQL API with the customer email, phone and address details. I get the response, everything looks fine (HTTP 200, no GraphQL errors, no userErrors). Even the response (data.cartBuyerIdentityUpdate.cart.buyerIdentity.deliveryAddressPreferences.0) contains the recently sent address.

SOMETIMES (very frequently) the customer has no prefilled delivery address on the checkout page, however the email is ALWAYS correct and updated.

I tried the funcionality with different datasets and scenarios. The most anoying thing is sometimes the previously validated and prefilled address "breaks" and will not work on the second try (but the email is updated). This makes me assume it is not the dataset that causes the problem, but now I do not have any idea.

I found a GitHub issue, might be related somehow: https://github.com/Shopify/checkout-sheet-kit-react-native/issues/77

Example X-Request-Id header: 42834fbf-3b11-4781-b504-81b178c7ba6c-1720018382

Could you help with this, please?

Thank you,

Gabor Bekesi @ BIG FISH

[gb-bigfish · Accepted solution]

After hours of debugging I managed to figure it out. The store has a configured delivery customization checkout UI extension. This filters the shipping rates and disables (hides) all the options. That makes Shopify to ignore the customer's delivery address preferences.

BUT when you're on the Shopify native checkout UI and you update your address details, it will be persisted even if the shipping it not available.