Problems with audio source

[Jubetsu]

I keep bumping into this problem with audio. When I open a file which does this, the only sounds coming from my headphones are ambient sounds and music. Not sure if this happens with other sources.

Not all files do this, but the ones that do, do it each time I open the file or sometimes when I apply subtitles or switch screen. This happens more with movies than series and the latest file was .mkv. Not sure if all of mkv do this, or if it's the only one type doing it.

To fix this problem I only need to switch audio source. Even if I switch to TV and back to headphones, I get full sound with no problem. I've been fiddling with the audio source from BS options but haven't noticed any change. Currently using "system default."

If needed, I can try different setups and filetypes to understand the problem better.