Kentico MVC Pages data type, error while attempting to loop related pages

Hi All, I have a Content-only Page type with a "Pages" data type field that links pages of different custom types from the parent document.

My intention is to loop through the Related documents as TreeNodes and grab link (NodeAliasPage) and link text (DocumentName) to create custom MenuItems.

I have tried every conceivable way to do this with the same result, exception thrown:

Object must implement IConvertible

I've tried this with and without the .Cast

    foreach (TreeNode page in footer.Fields.NavigationPages.Cast<TreeNode>())
    {
        // on second iteration the IConvertible error is thrown
        var menuItem = new MenuItemViewModel { MenuItemText = page.DocumentName, 
            MenuItemRelativeUrl = page.NodeAliasPath };
            vm.MenuItems.Add(menuItem);
    }

The issue seems to be that CMS.DocumentEngine attempts to cast the related item to the type of the first item in the collection on each iteration. And so on the start of the second iteration the error is always thrown. The first iteration works. Note: the first and second items have different Content-only Page types.

Is there a straight-forward solution for iterating through these docs in the "Pages" data type field? I am not doing anything custom in terms of querying this field. It comes populated with basic queries to the parent page.

Also tried these:

var noGo = footer.Fields.NavigationPages.Cast<TreeNode>().Select(x => new MenuItemViewModel
        {
            MenuItemText = ((TreeNode)x).DocumentName,
            MenuItemRelativeUrl = ((TreeNode)x).NodeAliasPath
        });

vm.MenuItems = footer.Fields.NavigationPages.OfType<TreeNode>().Select(page => new MenuItemViewModel
         {
             MenuItemText = "",
             MenuItemRelativeUrl = ""
         }).ToList();