Hi, @ervael and other readers
I'm currently on version 92.0.4561.43, and your fix doesn't work.
I had a red dot in the mobile app at calls, but that was from over a month ago and in stories. But the red dot wasn't there earlier today. Well, technically, it was, but when I had an unread message, I saw it and replied to it, and it was gone. Now when I open opera and reply to newer messages on the phone, it shows a red dot in the sidebar, it took a second to realize that message was read and even responded to, but the dot is still there.
I can open the messages, reload the messenger, restart the opera, and it's still there for hours.
Sometimes it is gone by itself, sometimes only after an opera update.
Edit: I'm now on version 92.0.4561.61, and it didn't fix itself after an update.