I'm using a child theme of twentyten. example.com/cpt/ redirects to archive-cpt.php as expected, but example.com/cpt/2011/02 goes straight to the 404 page.
As far as I know, it was working just yesterday and I haven't changed anything. It looks like the permalinks stopped working properly as printing the query array on the 404 page gives
Array ( [page] => /02 [cpt] => 2011 [post_type] => cpt [name] => 2011 )
How can I force it to write the correct query like it does for built in posts?
I've already tried refreshing the permalink settings but the problem still persists.