This looks like some new issue - different from previous. I'm hearing that the issue occurs in both the sandbox and in the production environments. For anyone who is seeing this issue - it's a bug report.
The first step (because it doesn't hurt to check) if the problem occurs only in the sandbox environment, create a new test user account to see if the problem is reproducible with the new ntest user account.
Assuming that the problem still occurs with the new test user account then submit the bug report as follows. (for those where the problem occurs with a production app, my instructions are simpler but I present them after the instructions the sandbox case.)
SANDBOX APP CASE ONLY
To submit a bug report, you are going to need to provide a means for the Apps Ops Engineering QA team to replicate the problem. You will need to have a TestFlight build ready so that you can send a TestFlight invitation to the Apps Ops Engineering QA team.
Please follow these steps.
1. Use the Apple Developer Bug Report web page - http://bugreport.apple.com to submit the bug report.
Select the “iTunesConnect” product for the new bug report.
2. In the bug report, please include the following
applicationID
steps to find the in-app purchase
iTunes Store that your test user account is associated with - US, Canada, Mexico, Japan, Chine, Germany, etc
Indicate that you will be sending a TestFlight invitation to use to replicate the situation
Indicate that you’ve tested with a new Test User account and that the same error occurred.
3. Save the bug report and send me the bug report number - rkubota@apple.com
4. Please send a TestFlight invitation to “apps_test@icloud.com”. In the invitation, IMPORTANT -please include the bug report number to associate the invitation with in the TestFlight invitation comments
PRODUCTION APP CASE
Please follow these steps.
1. Use the Apple Developer Bug Report web page - http://bugreport.apple.com to submit the bug report.
Select the “iTunesConnect” product for the new bug report.
2. In the bug report, please include the following
applicationID
steps to find the in-app purchase
iTunes Store that your test user account is associated with - US, Canada, Mexico, Japan, Chine, Germany, etc
3. Save the bug report and send me the bug report number - rkubota@apple.com
I will forward the bug report numbers to the Apps Ops Engineering QA team. They will replicate the issue, then forward the bug report to the iTunes Store Serever engineers when the problem will be investigated.
rich kubota - rkubota@apple.com
developer technical support CoreOS/Hardware/MFI