I'm not sure if this is Apple TV specific but I don't anything else to test this on. But on multiple Apple TVs, I have the following experience. When attempting to watch my virtual channel of King of the Hill episodes, the first episode plays just fine, and when the next episode begins, it plays without any audio. If you back out to the guide, wait a second or two, and go back in, the episode audio will now play.
This also happens to my Simpsons and old black and white monster movies virtual channels.
I am currently running the most recent beta that I have in Test Flight (1.18.1843) but this has been going on for the better part of the year. I'm not sure what is special about these particular videos when I have lots of other virtual channels that play next episodes just fine. Any thoughts would be appreciated.
Edit: I should mention that I have tried both the default and experimental audio driver and the behavior is the same for both.