Same issue with me!

I am having this exact same issue. I am attempting to get crash logs for an iOS iMessage app extension that has been distributed externally via TestFlight. On top of this Xcode organizer error, I am getting a message on Apple Store Connect under [App Name] > TestFlight > Feedback > Crashes stating I have "No Crash Feedback". This is despite TestFlight reporting 34 crashes. The documentation here clearly states that "TestFlight users of your app automatically share crash reports with you, regardless of the device settings for sharing diagnostic and use data." So I would expect some crash logs somewhere. I've created both a Technical Support Incident and contacted TestFlight support with my developer account. I'll update this forum with updates.