IOS 15.1 IAP restore behaves differently in xCode SDK Test than TestFlight.

We are testing IAP function with a Unity based app. The app is built with xCode 13.1, SDK for iOS 15, and UnityIAP 4.12. We noticed that for devices upgraded to IOS 15.1, IAP restore function works normally like other IOS versions, when testing through xCode. However, testing the same build through TestFlight, still on devices with IOS 15.1, the IAP restore function does not work at all. It is illogical that the app on the same device, built with the required xCode version, only installed through different routes could yield different results in tests. Does anyone have any idea why this could be happening?