RenderMvcControllerException.cs

// The below action works correctly when a template exists 
// for the current page. When a template has not been selected
// or does not exist, the ambiguous action method  
// exception occurs.
//
// I'm starting think this is correct behaviour because 
// MyPageController has an action called Index and so does
// RenderMvcController. Therefore, having duplicate routes.
//
// What I'm not quite certain about is why the exception
// only occurs when a view does not exist or when one has not
// been selected in the back office.

public class MyPageController : RenderMvcController
{
    public ActionResult Index(RenderModel model)
    {
        return new RedirectToUmbracoPageResult(model.Content.Parent);
    }
}