I have an app that uses StoreKit v2. It has a Non-Consumable InApp purchase. Using a development build and 2 sandbox testers, I tested this purchase many times and it worked perfectly.
I put the same app on TestFlight and invited 2 separate testers. When they try to purchase the Non-Consumable, they get the expected popup that says the purchase is free for TestFlight users. When they press purchase, they get a popup that says: Ask Permission, A request to buy "Unlock Game" will be sent to your parent or guardian, [Cancel, Ask]. Pressing any of these buttons does nothing and the purchase fails.
They do not have any parental controls enabled. They are able to purchase other apps with no issues.
We searched for related settings in App Store Connect and TestFlight and did not find anything.
What am I doing wrong? Why do InApp purchases in TestFlight show this popup?