I can see what you are talking about on your site, but I can't get this to happen on my pages. Are you working with the latest updated files for your PowerStore from the download center?
Do the products that are listed in the menu twice belong to more than one category?
As for the product details page did you make any edits to the menu? In the menu file that is located in the cssmw_home > menu.php page the links are only set to go to the Products_Results.php page.