Incorrect assignment of AuthTypes to Item Filters can cause issues in assembly.
For example, if you assign the All Content AuthType (sys_authtype=0) to the Unpublish Item Filter, assembly of Navigation and of other links will fail. This behavior occurs because, when building the links, the system looks at the AuthType and uses that to lookup the Item Filter. In this case, when building the navigation and other links, the system looks at the AuthType and finds it associated with the Unpublish Item Filter, resulting in all links (including navigation) being filtered out.
To debug this configuration, in the preview URL, change the sys_authtype HTML parameter to the sys_itemfilter parameter, with a value of a valid authtyp. In this example, change sys_authtype=0 to sys_itemfilter=preview. If the links are build correctly, check the Item Filters and ensure that the Auth Types are assigned correctly.