This is not actually an error, just lazy coding.
Basically, there are only two modes for the page listing - condensed (which shows pages 1-10, [11-whatever], and the final page) and expanded (which shows every page number). The "expanded" listing becomes viewable if you are either on the 11th page or later, or if you click on the link to show them.
That said, while it is possible to make it so that it shows only a certain range, and condenses the preceding and succeding ranges as needed, I (just speaking for myself here, not Illia, Dana, rale, or any of the other numerous code monkeys) don't think it's necessary.