Win10, last version and drivers

In short ... Sometimes all system sounds disappear in some automatic way. For example, if you poke the volume slider, it usually emits a sound, so I check it regularly and notice that the system sound is not stupid. Then it appears again. Sometimes it disappears again. At the same time, if it disappears on the speakers, I can switch to headphones (in the same tray, select another device) - there will be system ones. Back to the speakers - still no. Who faced? What's the catch? It seems that this is some kind of strange option in Windows.
Apart from these system sounds, there are no problems with sound at all. That's why I don't understand what's the catch.