I have recently implemented the Rest API, to create and capture orders (v2), and configured a listener for the relevant webhooks. All good so far. When we create the order, we provide the invoice_id, in the purchase_unit object. When a transaction is refunded, partially or in full, the original payee can see an input field 'Invoice ID' which is marked as optional. If that is left blank by the user, the webhook reflects the invoice_id from the original transaction and the automated reconciliation works as expected.
Where that is not left blank, then the invoice_id in the webhook is what ever has been entered into that field and I can't determine any other field that ties back to the original transaction (no parent transaction id for the paypal transaction being refunded) so my automatic reconciliation fails. Could you advise how to automatically identify the parent/original transaction when the invoice_id has been over written via the PayPal refund process?
