ATV 4k has to be rebooted to get video output

We use our ATV 4k as our home hub, so we have it set not to sleep. Frequently, after it has been idle for several hours, there is no video output. If we reboot it (holding home/menu buttons) the video returns. Generally speaking, after a reboot it is good until we stop using it for 24 hours or so.

We have it set for HDR to a Sony 4k HDR TV. If things are normal, the Sony TV reports the HDMI 2 connection as Apple TV (HDMI 2), just like it shows Dish Hopper (HDMI 4). If things are abnormal, and the Apple TV needs a reboot, the input menu on the Sony TV will show just "HDMI 2" on the input menu.

When there is no apparent video output, I have hooked the HDMI cable up to another TV and it shows no output either.

• I swapped HDMI cables and the problem persists.
• I swapped HDMI ports on the TV and the problem persists. (There are only 2 HDR compatible HDMI inputs)
• I have not tried turning off HDR and moving to a non-HDR port on the TV, as this would not be an acceptable solution even if it fixed the problem.

I suspect that the issue is tvOS update or HDR, as these are the only things that have changed in the past couple of months.

Is there something I'm missing?

Thank you.