Issue with pagination on nested category pages

Think i may have run into an issue with how the generation handles paging in the parent of nested category pages.

I've got the Glossary type of category. This category holds no pages, it holds categories each representing a letter for the glossary terms (a, b, c, d, e, etc).

On wordpress this works fine, and browsing to the parent glossary page displays all the pages within the child (letter) categories, with a pager.

On the static site however, only the 1st page is generated:
* /page/1/index.html

So it appears that is calculating the number of items based on the articles on that category alone, without considering the grandchildren