Hi,The part of our application is a finance game which is simple portfolio evaluation with real time market prices .We are selling consumable product for to improve user game scores in our application. That's why any delay in purchasing process creates serious disadvantage in user status.We have server-side validation based on client delivered receipt. The server-side validation fails when in_app array is empty in receipt and throws validation error. After Server returns Validation Error, client refresh receipt request with SKReceiptRefreshRequest and sends for server validation again. The case happens couple of times until server validation approved. The approved state has purchased product info in_app array. Also some of these cases we observe alphanumeric transactionIdentifier (transactionId) and for a while the transactionId replace with proper transactionId. Such as "75E75A0D-57A8-XXXX-XXXX-99949F0A61E5" became 6000XXXX480047 after new validation attempts of client.Our questions are Why the receipt retrieved after SKPaymentTransactionStatePurchased transaction state can contains an empty in_app array rather than the expected products. And what is the meaning of alphanumeric transactional identifier.How should we apply avoid to multiple server validation and Is there any suggested best practice exists about final receipt delivery to server to avoid server rejection? How should we check and be sure in_app array not empty in client? How can we speed up the flow.