I get the same thing. The Systems Settings icon shows up randomly in my dock with a red circle with a number "1" in it. I know what it's supposed to mean and most times I find the update ...because it's obvious it's a software update ...or possibly an app update. But most times, like now, there is no update. There is *nothing* I can find.
If I ignore it long enough, it goes away ...maybe for months. And then it shows up again. With nothing to show for it.
What's also annoying about it is when I click on the System Settings icon in the Dock, it *always* takes me to the Appearance Settings section ..and there is *never* anything in there needing attention; it's all user set options. Why can't this notification be made to take you to where the issue is? Or at least the General Settings section ...since that's where the updates are usually found.
[Edited by Moderator]