Url. Action() Including Route Values

I have an ASP.Net MVC 4 app and am using the Url.Action helper like this: @Url.Action("Information", "Admin")

This page is used for both adding a new and edit an admin profile. The URLs are as follows:

 Adding a new:       
 Editing Existing:    <==Admin ID

When I'm in the Editing Existing section of the site and decide that I would like to add a new admin I click on the following link:

 <a href="@Url.Action("Information", "Admin")">Add an Admin</a>

The problem however that the above link is actually going to . This only happens when I'm in that page editing an existing admin. Anywhere else on the site it links correctly to

Has anyone else seen this?

UPDATE:

RouteConfig:

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
        );