I'm not sure I've identified all ways to reproduce this bug, but here's one:
Open Start menu with the Windows button on your keyboard
Right click the MicMute icon in the notification area
Click elsewhere on the taskbar (or at all really) and annoyingly realize that clicking elsewhere will no longer close the menu as it should. You need to right click the MicMute button again.
I'm not sure I've identified all ways to reproduce this bug, but here's one: