Hi,
You may want to try the same site map with a standard ASP.NET Menu control and see if you get the same result. Our Menu uses the standard site map interface to get all the nodes and their properties. SiteMapDataSource can hide certain node from "outside". You can find more details from here:
http://msdn.microsoft.com/en-us/library/ms178428.aspxThis option hides a node if it is not accessible. You may have your custom site map provider that implements similar features but only hide the "url" attribute but still let the outside sees the site map node.
If the standard ASP.NET Menu demonstrates the same problem, then the problem is definitely on the sitemap side and you will need to troubleshoot that yourself. If standard ASP.NET Menu control works fine, then you can try to duplicate the problem in a separate test project and send it to us. We will be very happy to look into it and see what we can find.
Thanks!