Hello. It seems that apps that run in the background which has the option of having icon on the taskbar or notification bar, the icon doesn't display when starting said application. To get application with icon on taskbar/notification bar to display correctly, one must lock their session, then unlock the screen in order for icons to show up. So it seems to be something with refreshing the notification bar.
You could attempt alt+F2 then typing the command "r" this will restart gnome and reload the desktop which should resolve this. This isn't a permanent solution but it's certainly easier than locking and unlocking your session.
Do you know if this is a known issue? Is this an GNOME upstream issue or a Zorin theming type issue? Just trying to get a feel on what to expect for a future fix. Thanks.