Why setting font on label no longer works?

I upgraded everything to the latest (Xamarin.iOS 9.3.99.33, xCode, Xamarin Studio on my Mac) and the following code no longer works (the text on the label is blank). Anyone know why?

        var title = new Label
        {
            FontSize = Font.SystemFontOfSize(NamedSize.Large).FontSize
        };

Thanks in advance,

Mike