Apple TV 4K with Sony Bravia X800H problems

I have my Apple TV connected directly to my Sony Bravia X800H TV with a high speed HDMI cable. This is a new TV to replace an older Sony TV. The Apple TV worked fine with the older one, but now doesn't seem to work well with the new one. It seems I have to press the home button several times to wake the Apple TV and get the TV to read the signal. Then, when I select a movie to play from my collection, the TV intermittently loses the Apple TV signal. I have to go back to the input select on the TV, and select HDMI 2 again. It's as if the signal gets dropped if the Apple TV has to switch from SDR content to HDR content.