On Neon and looking at the panel tasks... there is this blue circle with a white zero that randomly appears on a task icon
It seems to stick to either of my web browsers or sometimes dolphin
If I change the sort behaviour (of the tasks) it will randomly assign itself to another task icon
But I can't figure out what that may indicate... help?

posting a screenshot/screencast will help with identifying what the problem is

Ok... was gonna post an image but as of this post, that 'artifact' is not there
When it appears, I shall post said image but to clarify, an image would have shown...
> a default panel... rendered with the default breeze dark theme
> there would be some tasks icons displayed
> on one of these icons--in the top right hand corner--there would be that blue circle with a white zero
I suspect it is a notifcation... but of what I don't know!

One thought (though not sure how likely nowadays since most things should be using the new APIs (and by new I mean the ones that have been around for most of KDE 4) which shouldn't have this problem) is a system tray app being rendered badly.
Another thought is if it were trying to render the number of notifications that an app has waiting, but none of the apps has any notifications so it's just putting that 0 on there randomly.

I don't know how plausible either one of those explanations is though.

airdrik wrote: ... Another thought is ...

Thanks for your input... I was also considering those possibilities
Fortunately--or not--with the past weeks updates to plasma 5.16.2 this particular oddity has yet to manifest
[But another old issue that was previously resolved is occurring again]

Finally an occurrence...

This artifact occurs with the Icons-only Task Manager widget
It would be nice if that notification would clear--as in no zero displayed--when a Dolphin file/folder process is completed
Buy hey... it is what it is!

Did you discover what that "0" means?
I also have it showing up on many of my icons in the task bar from applications that don't display notifications at all (like Okular or MySQL Workbench). And it seems like it won't go away until I close the application...
Using Kubuntu 20.04.