Disappearing audio on plasma-desktop

[dibl]

Is it only me, or have other plasma-desktop users noticed that the audio has recently disappeared from your desktop?  It just now happened for the third time in 2 days on my desktop, and I also saw it on my KDE laptop today.  It is restored with a reboot, but I haven't looked deeper to find out when and how it disappears.  Thanks for any ideas -- I assume a recent update introduced some instability related to this.

[jure]

disappearing audio means the kmixer speaker icon disappears ?
I have the same issue since a week or two - by starting kmixer from the multimedia menu, the icon come back....

System:    Host: siductionbox Kernel: 4.15.7-towo.1-siduction-amd64 x86_64 bits: 64 gcc: 7.3.0
                Desktop: KDE Plasma 5.12.2 (Qt 5.9.2) Distro: Debian GNU/Linux buster/sid

[dibl]

The volume icon remains on the panel, but it is gray and if you click it, it says "no device found". Next time it happens, I will try restarting kmixer from systemsettings.