How to fix volume changing by itself in Windows?

Question

Audio

I listen to music \ watch video \ etc (the main thing is that the sound stream goes on). There is some level of volume. I pause. After N seconds, I play again and the volume gets higher (system sound, not in the player). Through the Fn keys, I turn down the volume 1 time and it returns to the level that was before the pause.
Reinstalling drivers didn't help.
You can leave it like that (that is, the "does not work - remove Windows" scheme is not relevant), but the research interest is haunting.

Answer 1

spoiler

Answer 2

I even reinstalled Windows - nothing. What is your PC