The handleNavigation(FacesContext, String, String) method has some code that looks like this:
 
       wrapped.handleNavigation(context, fromAction, outcome);

        viewRoot = context.getViewRoot();
        NavigationCase navigationCase = getNavigationCase(context, fromAction, outcome);
        if (navigationCase != null && !navigationCase.isRedirect()) {
            viewMap = viewRoot.getViewMap();
            viewMap.putAll(propagated);
            if (null != oldDOM) {
                viewMap.put(DOMResponseWriter.OLD_DOM, oldDOM);
            }
        }

The problem is that the call to getNavigationCase(context, fromAction, outcome) happens too late. It has to happen BEFORE the call to wrapped.handleNavigation(context, fromAction, outcome). The way it is now, the wrapped navigation-handler has already put a new ViewRoot in the FacesContext, and subsequent calls to getNavigationCase(...) will fail and causes a FacesMessage like this:

Unable to find matching navigation case with from-view-id '/views/bar.xhtml' for action '#{backingBean.submit}' with outcome 'success'