how do i display consistent post data

I'm using shortcode to display a combination of normal posts and custom posts with the code [display-posts category="category" image_size="thumbnail"]

I have a list of posts and a list of custom posts, each has a category assigned to it.

I am displaying the posts across 4 pages (one top menu page and then three subsequent sub-menu pages).

on the top level page it is displaying the custom post types and on the sub-menu pages it is displaying standard post types even though both post types have the same categories assigned to them.

I have changed the settings in 'Categories'. initially there were three categories with a parent category and i have experimented changing this so that there are no parent categories but this has no affect.

does anyone have any suggestions?