Here is a post from January 2026 with additional details: https://developer.apple.com/forums/thread/814292 This appears to still be a problem.

I can't believe this issue first reported in November (https://developer.apple.com/forums/thread/806407) is still ongoing. We are stuck on this one

We are having the same issue. We are not using Unity, fetching through Store Kit (which is same as what Unity does anyway). Fetching the products suddenly stopped working on TestFlight and development builds. App store builds appear to be unaffected right now