Zoom Windows Desktop app shows a notification when there are no unread messages

Zoom Version: 5.17.7 (31859) on Windows 10 Enterprise 22H2.

Zoom recently (last few weeks) started showing a notification (red disc containing white number) on the desktop app, both on the launch bar at the bottom of the screen, and in app against 'Team Chat'. 

I have checked, and there are no unread messages.  I have cleared chat histories, left chats etc, but still the notification is displayed. I have restarted the app, restarted the machine, reauthenticated and still the notification is displayed.

I am out of ideas, and while this is not my #1 work priority, it is distracting as it makes me wonder if I am missing an important notice I can't see.

I saw this was an issue for some users a few years ago, but I didn't find anything useful that was more current.  Please help.