Ship to multiple addresses does not work

[Danil2005st]

Description
When Custom Checkout is enabled for a store, the checkout configuration returned to the front end contains different feature flags compared to when Custom Checkout is disabled. In particular, hasMultiShippingEnabled is returned as false with Custom Checkout ON, even though multi‑shipping is enabled in the store settings and the same store returns hasMultiShippingEnabled: true when using the default checkout. This causes custom checkout flows to behave as if multi‑shipping is disabled.

To Reproduce
In BigCommerce admin, enable Multi‑Shipping (Store Setup → Shipping → Multi‑Shipping → Enable).

Ensure the same store is used for both cases and clear cookies/cache between tests.

Case A — Default checkout (Custom Checkout OFF):

Turn Custom Checkout OFF in admin. checkout-settings?checkoutId=checkoutId

Open storefront checkout URL and capture network traffic that contains checkout config.

Case B — Custom checkout (Custom Checkout ON):

Turn Custom Checkout ON and configure it to point to a local or remote auto-loader.js as appropriate.

Open the same storefront checkout URL and capture the same network response.

Compare the two JSON responses: note that hasMultiShippingEnabled is true in Case A and false in Case B.

Expected: same checkout configuration (features) for both flows; specifically hasMultiShippingEnabled should reflect the store setting regardless of Custom Checkout toggle.

Actual: hasMultiShippingEnabled is false when Custom Checkout is ON; other feature flags may also differ.

Expected behavior
The checkout configuration returned to the front end for the same store should be consistent regardless of whether the store uses the default (optimized) checkout or a Custom Checkout. If multi‑shipping is enabled in store settings, the config should include hasMultiShippingEnabled: true for both flows (or provide clear docs/contract that explain the difference and how to enable it from the custom checkout).

[bc-peng]

Hi there, I was unable to reproduce the issue using the exact steps you provided.

As shown below, storeConfig.checkoutSettings.hasMultiShippingEnabled has the same value in both default and custom checkout. All screenshots were taken in a new incognito browser session.

[Danil2005st]

Hi @bc-peng . Thanks for checking this. We’ve identified the reason for the behavior: it depends on the checkbox in checkout settings labeled “This checkout supports Optimized One‑Page Checkout settings.”

When this checkbox is selected, the hasMultiShippingEnabled flag in the checkout config reflects the value from the admin settings.

When it is not selected, the flag is always returned as false, regardless of the admin configuration.

This explains why we consistently see false in our case.

Does anyone know what other settings or feature flags this checkbox influences? It would be helpful to understand the broader impact of enabling/disabling it.