During my first external test using TestFlight for an In-App Purchase (iPadOS), the user was
(1) Prompted for their Apple ID & password
(2) Prompted for their password a second time
(3) (User believes) prompted for their password a third time
Are these multiple prompts for their password expected behavior, or have I done something wrong?
Follow-up:
I get the same behavior (enter Apple ID + password, followed by entering password twice more) for first IAP in both TestFlight and when using a sandbox account.
A second IAP purchase works as expected (enter your password just once).
I took Apple's StoreKit 2 demo app, changed the Bundle ID, created an app on App Store Connect with all the same IAP items in the demo, and purchased items through a sandboxed account. I get the same behavior from Apple's demo code: enter Apple ID + password, followed by entering password twice more.
I went ahead and submitted the app for review. I hope the non-TestFlight and non-Sandboxed behavior (i.e., a real user purchase) is better. Fingers crossed!
Follow-up 2:
The app was approved, and I tested the In-App Purchase. It worked as expected! :-)
So it appears all the extra passwords required (3 altogether for the first purchase) for Sandboxed user and TestFlight testing is just an artifact of the testing process.