UPDATE: I just installed the store on another DNN 7 site. I got the same issue with theNB_Store_CategoryMenu Module. In the NB_Store_CategoryMenu Settings tab the default page forProduct List Tab was Admin/Security Roles. I have no idea why this would be the default. But it caused that page to be called each time I selected a Category. I changed it to Store and that fixed the problem.
Regards,
Gary