Permanent Strawberry Symbol in Notification Bar sometimes vanished [Linux Mint 20.1]

[therob]

For me Strawberry 0.8.5 initially had a permanent Symbol in the "Notification bar" on the lower right corner of my LinuxMint20.1-Taskbar (nearby clock, battery, bluetooth symbols) doesn't matter of program window is maximized, minimized or closed, it is also showing progressbar if played a song.

Sometimes this symbol is just not visible - but after closing (Music->Exit) and restarting strawberry or a restart of Linus Mint (Strawberry is in autostart) it is back, but not always.

What could be checked to find out the reason that it is not ALWAYS there while it is vanished?

Normal program symbol in taskbar is visible until I close window.

Cheers, Robert