Wikimedia Bugzilla is closed!

If I list the categories of some page in ascending order:

https://en.wikipedia.org/w/api.php?format=xml&action=query&titles=Test&prop=categories&cldir=ascending&cllimit=1

I get query-continue that works fine.

But if I use descending order:

https://en.wikipedia.org/w/api.php?format=xml&action=query&titles=Test&prop=categories&cldir=descending&cllimit=1

then the query-continue value doesn't seem to have any effect: I get the same category as originally and the same query-continue.

I am using limit=1 just to make the query simple, but the same problem shows also in “real” queries that use generators.