Filter returning all content types when 2 types selected

I have a few different content types (page, book, research, news media etc). Most fixed content uses "page" as the content type. I want users to submit content such as books that are relevant to a topic.

I noticed that when I used the following link ( taxonomy/term/41?type=book ) many of my menus disappeared because the menu items pointed to "page" content type destinations. I found the reason for this on the Drupal site here ( http://drupal.org/node/248820 )

So, I figured, if I use the following link ( taxonomy/term/41?type=page,book ) I should have no problem. It should show the "book" articles and should also show the "page" articles and links. But, I seem to be getting articles that have other types such as "story" appearing. Of course, the article contains a taxonomy term 41, but I thought that the node type filter should remove the "story" articles. I've also tried ( taxonomy/term/41?type=page+book )

Do you have any ideas why I am not getting the right results?