Last modified: 2013-07-25 19:18:32 UTC
If you look at page settings under https://sv.wikipedia.org/wiki/Violin?veaction=edit you'll see the category "Wikipedia". This is actually Kategori:Wikipedia:Basartiklar if you look at the page source; it seems the VE isn't including category elements that are preceded by a colon.
This style of category name also appears at de.wikipedia, e.g., [[:de:Kategorie:Wikipedia:Schnelllöschen]].
Change 75859 had a related patch set uploaded by Esanders: Parse category names correctly https://gerrit.wikimedia.org/r/75859
Change 75859 merged by jenkins-bot: Parse category names correctly https://gerrit.wikimedia.org/r/75859
Now fixed in master.