There is also another report here
From what I figured out how this Bug manifests itself.
There are exactly as many unnamed “Disconnect” shown as there are named Wi-Fi networks overall, but if you click on one of unnamed Disconnects they multiply as well.
Looks like @Laurentiu_Bodlev has not reported it yet at bugs.kde.org (or not for the plasma-nm applet)?
At least I did not see it, but the sorting of the Bug-list is a little bit confusing to me, maybe just missed it. If I still don’t see it this Weekend I will report it there myself, but have to figure out what mail/username I have used there or if I have to create a new one first because it is a while since i last used it. 