I have noticed that when you install Testflight apps, they show as updates in the App store. And one other big issue I have which will hopefully correct itself. I tried downloading Airmail from Testflight and it tried installing from App Store at the same time. Now they just both show the round circle with the stop button in the middle & pressing it does nothing from either the App Store or Testflight, so it's like frozen trying to install from both Testflight & App Store.
