What I have observed:
When using "automatically manage signing", Xcode 11 will generate a provisioning profile with development certificates even for distribution. But during the archive where we upload to TestFlight (or export an .ipa), Xcode will re-sign the app with the right distribution certificates (that it will offer to generate if not found).
However, Xcode won't associate this distribution certificate that it generated back into the provisioning profile.
Problem:
My building machine - in this case BitRise - can't archive the app for app-store mode because there is no distribution certificate found in the generated provisioning profile.