Volume Shortcuts doesn't work in KDE Plasma

The problem is just the volume shortcuts doesn’t work. I tried using KMix instead of plasma-pa but that was a temporary solution. How can I make volume shortcuts work again? Thanks.

Also I saw other posts covering the same problem, the solutions they gave didn’t work.

Edit: After 10 reboots, it got fixed.

See my last post about system tray. There’s a link that might help give a more concrete solution. The media player icon in system tray might be a culprit.