We found the root cause and resolved the issue.
If we run below admin GraphQL query externally (via Postman or fetch API call) with the access token we generated from the store itself. “shopifyFunctions” will always return an empty list.
query {
shopifyFunctions(first: 10) {
nodes {
id
app {
title
}
}
}
}
If we install GraphiQL tool from Shopify with the same access scopes, and run the same query. We are able to get the expected function output from the “shopifyFunctions” list, then bind the function id into cart transform API correctly.
Thank you.