We just upgraded from Umbraco v 4.11 to v 6.1 and have noticed that a certein Razor randomly functions improperly. I is supposed to pull items from folders within the media library, but every so often it skips certian media folders and doesn't pull their documents into the list on the page. Here is the Razor, could someone look it over for errors please?

@inherits umbraco.MacroEngines.DynamicNodeContext

@{
    if ( String.IsNullOrEmpty(@Parameter.mediaFolder) ) {
        <div><p>A folder has not been selected</p></div>
    }
    var folder = Parameter.mediaFolder;
    var media  = Model.MediaById(folder);
}

@helper traverse(dynamic node) {
    var cc = node.Children;  
    if ( cc.Count()>0 && node.NodeTypeAlias == "Folder" ) {
        <ul>
            @foreach (var c in cc) {
                <li>
                    @structure(c)
                    @traverse(c)
                </li>
            }
        </ul>
    }
}
@helper structure( dynamic node ){
    if ( node.NodeTypeAlias == "Folder" ) {
        <span class="folder" id="@node.Name.ToLower().Replace(" ", "_")">@node.Name</span>
    } else {
        <a href="@node.Url" target="_blank">@node.Name</a>
    }
}
<div class="formWrangler">
    @traverse(media)
</div>