Firebase App Check with Firebase App Distribution

Question

I have setup App Check with very little issues and it is working for the production release of my app. However, I get permission denied for all Firebase requests from the internal testing version of my app that is distributed through Firebase App Distribution. I have copied the SHA-256 test certificate for the AAB from the App Distribution page into the Play Integrity section of App Check. Our test users are downloading the internal testing version from the Play Store by following a link from the Firebase App Distribution app. I also installed the internal test version on my personal phone and got permission denied errors. The release version works fine, for everyone including the testers but the internal testing version does not. In addition I looked at the SHA-256 key for the internal test version on the Play Store Console. It was exactly the same as the App Distribution key. Both the release version and testing are identical, once testing is complete the testing version is promoted to beta. Then beta is promoted to production. Again, Beta and Production both work fine. Any ideas about why the testing key would not work?