When switching to your Apple TV input you may encounter a situation where instead of the standard Apple TV home screen, you may instead be taken to a different home screen. Most likely you were taken to the Apple TV app. This can be verified by looking at the top row of menu items. If you see 'Watch Now' as the first menu item then you are in the Apple TV app. What may have happened is that remote control 'Home' button assignment may have been changed from 'Home Screen' to 'TV App'. To fix this please do the following...
1. Go to the Apple TV 'Settings' menu
2. Select 'Remote and Devices'
3. Go to 'Home Button' tab and and see if it says 'Apple TV App'. If that is the case, select the 'Home Button' tab and change it to 'Home Screen'.