To reproduce run attached code.
Click on some application to lose focus. And wait 3 seconds.

On Macos you won't get focused state(just like toFront method).
On Windows you will get focused property equals true, but application won't receive input from keyboard

public class Bug extends Application {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
        // TODO code application logic here
    }

    @Override
    public void start(Stage stage) throws Exception {
        stage.setScene(new Scene(new HBox(new Button("One"),new Button("two")), 200, 200));
        stage.show();
        new Thread(() -> {
            while (true) {
                Platform.runLater(() -> {
                    stage.requestFocus();
                    
                        });
                try {
                    Thread.sleep(3000);
                } catch (Exception ex) {
                }
            }
        }).start();
        new Thread(()->{while(true){
            Platform.runLater(()->System.out.println("Focused"+stage.isFocused()));
            Platform.runLater(()->System.out.println("Showing"+stage.isShowing()));
            try{
                Thread.sleep(2000);
            }catch(Exception ex){
                
            }
        }}).start();
    }

}