1 Answer
The cart docs on Shopify seem to show they want "merchandiseId" to start with "gid://shopify/ProductVariant/" so I guess you should replace yours with the same value, but this at the front of it.
The cart docs on Shopify seem to show they want "merchandiseId" to start with "gid://shopify/ProductVariant/" so I guess you should replace yours with the same value, but this at the front of it.