I have similar problem. I uploaded a version to testflight with an internal group which build distribution set to automatic. I tried to change text of the Test Details. I tried to add a dummy group with manual build distribution, and adding it to the version group. Still not working. I tried to add/change test information for the app. Not working Please help

Same for me I uploaded app to testflight, I release the app but it doesn't accept any internal test groups