My first idea was to use "refreshLinks.php" to help the cause. Since this did not work I used "recountCategories.php" followed by "cleanupEmptyCategories.php". While the first two mentioned scripts actually cleaned up some other stuff, the last one just emitted "...Update 'cleanup empty categories' already logged as completed."
However I still see the artifact category on this special case.
Is there another script I could try to use here? I personally did not find something else which could potentially be adequate for this.
I suspect I might even have found a bug to report here. However I would like to check back for other opinions first.
In the end no big deal to have this cat or not but still ...
Thanks for you time and help. Cheers