In iOS 26.4 beta 4, the receipt returned by StoreKit payments via [[NSBundle mainBundle] appStoreReceiptURL] corresponds to the previous transaction; the content only becomes correct after restarting the app.
StoreKit API anomalies in iOS 26.4 Beta 4
No restart is required; simply delaying the call to [[NSBundle mainBundle] appStoreReceiptURL] by 1 second resolves the issue.