I've been working with the orderEditCommit GraphQL endpoint (https://shopify.dev/docs/admin-api/graphql/reference/orders/ordereditcommit) to add a product to a order. I can manually create an order via the Admin UI. Then, using a private app in my store with full credentials, my code can add the product to the order with the notifyCustomer flag set to true and I receive an email when the order is edited. While testing, everything works fine.
When I create an order through our store, we use Carthook Checkout and it is installed as a private app in our store and it creates the order on our behalf. At first, I ran into an error saying that the order can only be edited by the app that created it. So I updated my code to use the Carthook Checkout credentials and now, I can add the product to the order, but I do not receive an email even though the notifyCustomer flag is still set to true.
What other logic is driving whether or not an email is sent to the customer?
Are there specific permissions required for the private app to be able to send an email when an order is edited?