I filed a bug in Feedback Assistant for this issue https://developer.apple.com/forums/thread/711307 (FB10941060). Apple didn't reply, so I attempted to file a Technical Support Incident to have an engineer at Apple investigate the issue. (Follow up 805401346)
DTS replied saying that they refuse to investigate any issues in App Store Connect, including the App Store Connect API.
This is not OK! When there are critical problems with the App Store Connect API, there has to be some support channel I can use to get an Apple engineer's attention.
What can I do here?
Thank you for contacting Apple Developer Technical Support (DTS). We provide support for code-level questions on hardware & software development, and are unable to help you with your question.
For questions regarding App Store Connect, we recommend that you first check the App Store Connect Help:
https://help.apple.com/app-store-connect/
If you are not able to find the information you need in the App Store Connect Help and you are still not able to resolve your issue, please direct your inquiry through the Contact Us page:
https://developer.apple.com/contact/
Submitting an inquiry through the Contact Us page will expedite the response time from the proper Apple representative.
When contacting the App Store Connect Team, be sure to mention that you were referred by DTS.