I am having this exact problem. Locally I can test with .storekit file and the entire flow works great. The moment I submit the app and the status of subscriptions change to "Waiting for Review", Storekit stops fetching the subscriptions and .storekit file removes previously available subscriptions once I click "Sync". Because of this, everytime I click on "Submit for review" the flow breaks basically resulting in App rejection. And I wasn't able to explain this to the Apple reviewers. If anyone has an idea how to resolve it, it would be greatly appreciated.

Thank you for replying! If that's the case, it is not an implementation issue but a Xcode problem, right? Have you seen such an issue posted somewhere?