the information described in this internet post is additionally impacting myself

Yes and no. I found a workaround which was to create a new testing group with the build distribution set to 'Manual for Xcode Builds'. My QA and Product team members are in that. Whenever a new build shows up in test flight, I have to manually make it available to that group, rather than it automatically doing so. I could only seem to do this when creating a new group though, not able to change this setting on a group after it has been created.