Thank you for your reply, and I apologize for not providing enough detail earlier. Our app is built with React Native, and we implemented in-app purchases using an OpenIAP-related library that supports StoreKit 2. We are currently testing with a Sandbox account. The feature itself is not completely broken, but we are seeing several abnormal behaviors during testing. For example, even when a purchase is attempted only once, we sometimes receive the purchase-completed message two or three times. We have also observed other inconsistent behaviors during Sandbox testing. Because of this, we were wondering whether this might be related to instability or known issues in the Sandbox environment, rather than being entirely caused by our implementation. Has anyone experienced similar issues when testing subscriptions with StoreKit 2 in a React Native environment? If there are any known Sandbox limitations or specific points we should check first, I would greatly appreciate your advice.