I’ve had this problem since sometime during my time on plasma 5.10. Today I upgraded to 5.11 and the problem is persisting. The icon for the volume applet has disappeared. The applet still functions: I can open the settings, hover my mouse over the blank space and adjust volume, etc. I tried installing the kmix package and experienced the same behavior with its applet, so I removed the kmix package. I can’t find any recent posts anywhere asking about this issue. Any else experiencing it or have an idea for a fix? It’s only a minor annoyance but I am curious. Thanks.