EDIT: nevermind, I just heard it happen on Netflix as well. Bummer.
Server Version#:1.28.2.6151
Player Version#:9.8.2.35221 (75113949)
Difficult to describe, the sound is like someone trilling their tongue or perhaps like when a person puts playing cards on a bike to make the spokes hit it while in motion to make a noise. This has been doing this for a couple of patches at least.
Thankfully the latest patch fixed the Home screen TV section naming issue, however this audio trilling noise is still present. It’s very brief, lasts less than a second I would say.
It doesn’t seem to matter what the file type or audio type is. Strange.
I believe the setting you’re looking for is “Play comfort noise over HDMI.” It plays inaudible noise to prevent the cracking. I’m not home to check the exact location of it. I think it helps but doesn’t completely get rid of it in Plex. I found it much better to disable passthrough. But it might work better for your setup.