c# - ASP.NET MVC 4 bundles includes unexpected resource

Question

I'm startin using ASP.NET MVC "Bundles and Minificatiom" feature. That's my bundle registration code:

public static void RegisterBundles(BundleCollection bundles)
{
    BundleTable.EnableOptimizations = false;

    bundles.Add(new StyleBundle("~/Assets/bundles/css")
                .Include("~/Assets/styles/style1.css")
                .Include("~/Assets/styles/style2.css")
                .Include("~/Assets/styles/style3.css")
    );
    //....
}   

... and in *.cshtml file it's rendered by this code:

@Styles.Render("~/Assets/bundles/css")

But, when I set BundleTable.EnableOptimizations = true, my resulting (joined and minified) css-stylesheet includes classes from style4.css file.

As you can see, this file isn't included in bundle. Where is my mistake?