The "Edit links" link doesn't work in categories named "Wikipedia:" - at least I've seen it at dewiki and I think it also happened in eswiki. I think the problem is that the feature is puzzled by two space names in a row - it can't tell apart what is the space name and what is the page name.
Example: in https://de.wikipedia.org/wiki/Kategorie:Wikipedia:Redundanz_Februar_2015 , when trying to link it to cawiki, it gives the error: "The external client site 'dewiki' did not provide a page information for page 'Wikipedia:Redundanz Februar 2015'.
Please notice the absence of "Kategorie" in page name in the error message. That's why I think it has ha problem identifying space name.