Sometimes there is no sound when I switch from the YouTube app to TV using the TV button
If the audio cuts out when switching from the YouTube™ app to the TV, press the TV button on the remote control again to hear the TV's sound.
What causes this temporary audio loss?
Android apps need to acquire Audio Focus (the right to play sound) before outputting any audio. The sound may occasionally disappear if more than one app (e.g., YouTube, TV) acquires Audio Focus at the same time.
For example, on YouTube's Home screen, if you highlight a video and wait for around three seconds, a video preview starts playing, and YouTube acquires Audio Focus. However, if you press the TV button right when the YouTube preview acquires Audio Focus, the TV app will also try to acquire Audio Focus at the same time. In rare cases, the timing may cause the YouTube preview to keep the Audio Focus instead of the TV app, resulting in temporary audio loss.