Hi. I'm using another plugin called 'Easy' to display a list of posts. It supports wp-pagenavi.
It works fine on this page, which pulls from a top level post category:
But it doesn't work on this page, which pulls from a second level post category:
Category: News -> Press Releases
I posted this to the plugin author for Easy and he has been very helpful and says it is wp-pagenavi that is not working properly in this case.