Why 24fps is not enough for HDR movies

[Game500]

I have an Insignia NS-43DR710NA17 4K UHD Roku TV in my bedroom purchased about a year and a half ago, but recently, I noticed that my volume auto-mutes.

I contacted Insignia a while ago, and tested on the remote using the following procedure:
*Remove batteries
*Test each button beginning with the top

After which, I still get the same auto-mute problem.

What possible solution could happen?