ASP.NET MVC全局授权过滤器强制登录AllowAnonymous操作

public class MyAuthorizeAttribute : AuthorizeAttribute {

    protected override bool AuthorizeCore(HttpContextBase httpContext) {

        var isAuthorised = base.AuthorizeCore(httpContext);

        if(isAuthorised) {
            // retrieve authentication ticket from cookie and
            // create custome principal and attach to 
            // httpContext.User
        }

        return isAuthorised;
    }
}

Gloabl.asax.cs：

public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
    filters.Add(new HandleErrorAttribute());
    filters.Add(new MyAuthorizeAttribute());
}

HomeController.cs：

using System.Web.Mvc;

public class HomeController : Controller
{
    [AllowAnonymous]
    public ActionResult Index()
    {
        return View();
    }
}

问题

对主页的调用强制登录页面加载.

题

当HomeController.Index()动作用[AllowAnonymous]装饰时,为什么ASP会将我重定向到登录视图？

我使用this文章作为参考