SiteMapNodes not showing after upgrade from Unity to autofac

Question

We had a development house upgrade our site to use Autofac instead of Unity and now our sitemap is empty - we no longer have our menu items nor do we have our breadcrumb trail. From debugging all I can say with certainty is that our sitemapNodes are empty (Only the root shows up) - running the old and new side by side everything happens in extenral code so I have no idea where it's going wrong. We use a custom implementation of the SiteMapNode to identify our menu items like below

 [AuthorizeRights(SystemRights.MyRights)]
        [MyCustomMvcSiteMapNode(LocalizedTitleKey = "MyObject_IndexTitle", ParentKey = "MyObject", Key = "MyObjectIndex", ShowInBreadCrumbOnly = true)]
        public ActionResult Index()
        {
            var list = _myObjectLogic.GetMyObjects();
            var viewModel = new MyObjectsViewModel(list);
            return View(viewModel);
        }

In the old version the code just finds the pages and lines them up in the menu, but in the new code nothing.

I've searched ad nauseum and found countless pages that tell me things like "You need to install these Nuget Packages" or "If you're using OWIN you need this code at startup" but none of it worked.

Can anyone tell me what we are missing?