Flutter: Hot reload and Routes

I noticed that when I extend MaterialPageRoutes and then instance them like this

class Route extends MaterialPageRoute {
  Route(): super(
    builder: (context) {
      return SomeWidget();
    }
  );
}
...somewhere in the build method of another class...
Navigator.push(context, Route())

a hot-reload will not rebuild the contents of the route like it does when I do

...somewhere in the build method of another class...
Navigator.push(context, MaterialPageRoute(
  builder: (context) {
    return SomeWidget();
  }
))

or

class Route extends MaterialPageRoute {
  Route(): super(
    builder: (context) {
      return RouteWidget();
    }
  );
}
class RouteWidget extends StatelessWidget {
  Widget build(BuildContext context) {
    return SomeWidget();
  }
}
...somewhere in the build method of another class...
Navigator.push(context, Route())

I find it especially weird that the last work-around works. Any idea what I'm missing? The documentation says that a hot-reload will rebuild all widgets.