Action is called twice - asp.net-mvc-4

Question

All, I encountered a problem which MVC action is called twice. Please help to review it.
The view code is simple.
<div class="divContainer">
<ul>
#foreach (var blobName in ViewBag.BlobList)
{
<li>#Html.ActionLink("Delete", "Delete", "LogBlob", new { blobUrl = blobName }, null)</li>
}
</ul>
</div>
public class LogBlobController : Controller
{
public ActionResult Delete(string blobUrl)
{
//...
//The action is call twice.
}
}
Since the LogBlobController belong to an MVC Area named Log. So the route config in the AreaRegistration looks like below.
public class LogAreaRegistration : AreaRegistration
{
public override string AreaName
{
get
{
return "Log";
}
}
public override void RegisterArea(AreaRegistrationContext context)
{
context.MapRoute(
"Log_default",
"Log/{controller}/{action}/{id}",
new { action = "Index", id = UrlParameter.Optional }
);
}
}
And the default implement of RouteConfig of MVC is below.
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Login", action = "Login", id = UrlParameter.Optional }
);
}
And the Html in the page looks like below.
Delete
I doubted the reason of twice is they(LogAreaRegistration and RouteConfig) both worked at the same time. thanks.