At the moment, we have one auto-renewable subscription on our live app, and we want to add two more, where the only difference is the price and the subscription time. To accomplish that, we created a "subscription group" and everything is set up on the apple side:
and the app is currently reading all the packs from the store and allow the user to buy them.
Our issue is that we can't fully test the upgrade/downgrade feature when trying to buy another subscription level on sandbox (iOS 14.5). If we buy the lowest pack first, and then try to buy a superior pack, a popup should appear saying that we want to modify our current subscription plan to another one and that it will start on XX/XX/2021 as seen here (image from a tutorial):
This is not the behaviour we are seeing on our app (on sandbox). When we try to buy a superior plan the app shows the normal purchase popup:
and it proceeds to buy the pack normally without showing the popup warning that we are changing our current plan.
This causes some concerns, as it implies that the user is buying two subscriptions. They are on the same subscription group, so it should be impossible, but still brings concerns... Did anyone experienced the same issue? Is this the normal behaviour in sandbox?