Maps with callout shown not filling the screen after changing orientation

We have a Xamarin Forms (2.0.0.6490) app which uses Xamarin.Forms.Maps.Map (2.0.0.6490), but it looks like the map won't fill the screen if we rotate the iPad from landscape to portrait and then rotate it back to landscape while a callout view is shown. It will leave a blank space to the right of the screen. This won't happen if the callout is not shown. We tested this in iOS 9.2 (13C75) only. Here is an example that can demonstrate this. It shows a map which fills the full screen, and there is a pin in the map. Click on the pin to show the callout, and then rotate the device from landscape to portrait and rotate it back.

This seems to be a bug, but I like to make sure I didn't miss anything in my code. Any one had similar experience?

    [Register ("AppDelegate")]
    public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
    {
        public override bool FinishedLaunching (UIApplication app, NSDictionary options)
        {
            global::Xamarin.Forms.Forms.Init ();

            Xamarin.FormsMaps.Init();

            LoadApplication (new App ());

            return base.FinishedLaunching (app, options);
        }
    }

    public class App : Application
    {
        public App ()
        {
            var map = new Map (MapSpan.FromCenterAndRadius(new Position(0,0), Distance.FromMeters(5))) {
                HorizontalOptions = LayoutOptions.FillAndExpand,
                VerticalOptions = LayoutOptions.FillAndExpand,
            };
            map.Pins.Add (new Pin {
                Label = "test",
                Position = new Position (0, 0)
            });

            MainPage = new ContentPage {
                Content = map,

            };
        }
    }