Here is a code with "teleportation" problem.


Start code:
....
....
public class JavaFXApplication1 extends Application {
.....
.....

    @Override
    public void start(Stage primaryStage) {
        //test(primaryStage);

        final Human human=new Human();
        final Human human2=new Human();
        
        final Group root = new Group(human,human2);
        Scene scene = new Scene(root, 300, 300);
        scene.setOnMousePressed(new EventHandler<MouseEvent>() {
            
            @Override
            public void handle(MouseEvent t) {
                human.runTo(t.getX(), t.getY());
                human2.runTo(t.getX()-70, t.getY());
                //System.out.println("KK");
            }
        });

        scene.setOnScroll(new EventHandler<ScrollEvent>() {

            @Override
            public void handle(ScrollEvent t) {
                System.out.println("Scrolling! "+t.getDeltaY());
            }
        });
        
        
 Rectangle2D primaryScreenBounds = Screen.getPrimary().getVisualBounds();

 //set Stage boundaries to visible bounds of the main screen
// primaryStage.setX(primaryScreenBounds.getMinX());
// primaryStage.setY(primaryScreenBounds.getMinY());
// primaryStage.setWidth(primaryScreenBounds.getWidth());
// primaryStage.setHeight(primaryScreenBounds.getHeight());
        
 //primaryStage.setFullScreen(true);
 //primaryStage.setIconified(false);
 //primaryStage.setOpacity(0.1);
 primaryStage.initStyle(StageStyle.TRANSPARENT);
 //primaryStage.getOwner().setOpacity(0.2);
 
        primaryStage.setScene(scene);
        primaryStage.show();


    }
....
....
....
}



Class with "teleportations":

package game.human;

import javafx.animation.*;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.Scale;
import javafx.util.Duration;

/**
 *
 * @author Me
 */
public class Human extends Group{

    private Image imghuman = new Image(Human.class.getResource("images/human.png").toString());
    private Image imghumanR = new Image(Human.class.getResource("images/human_r.png").toString());
    private Image imghumanR2 = new Image(Human.class.getResource("images/human_r2.png").toString());
    private Image imghumanL = new Image(Human.class.getResource("images/human_l.png").toString());
    private Image imghumanL2 = new Image(Human.class.getResource("images/human_l2.png").toString());
    private ImageView human = new ImageView(imghuman);
    private ImageView humanR = new ImageView(imghumanR);
    private ImageView humanR2 = new ImageView(imghumanR2);
    private ImageView humanL = new ImageView(imghumanL);
    private ImageView humanL2 = new ImageView(imghumanL2);
    //private Group HUMAN;
    private TranslateTransition current;
    private Timeline LEFT_MOVEMENT;
    private Timeline RIGHT_MOVEMENT;
    private static final double SPEED=50;
    final Human SELF;

    public Human() {
        super(new ImageView(new Image(Human.class.getResource("images/human.png").toString())));
        SELF=this;
        init(this);
        //this.getTransforms().add(new Scale(0.1,0.1));
    }

    
    
    
    private void init(final Human me){
        LEFT_MOVEMENT = TimelineBuilder.create().cycleCount(Animation.INDEFINITE).keyFrames(
                new KeyFrame(new Duration(250), new EventHandler() {

            @Override
            public void handle(Event t) {
                me.getChildren().setAll(humanL);
            }
        }),
                new KeyFrame(new Duration(500), new EventHandler() {

            @Override
            public void handle(Event t) {
                me.getChildren().setAll(humanL2);
            }
        })).build();




        RIGHT_MOVEMENT = TimelineBuilder.create().cycleCount(Animation.INDEFINITE).keyFrames(
                new KeyFrame(new Duration(250), new EventHandler() {

            @Override
            public void handle(Event t) {
                me.getChildren().setAll(humanR);
            }
        }),
                new KeyFrame(new Duration(500), new EventHandler() {

            @Override
            public void handle(Event t) {
                me.getChildren().setAll(humanR2);
            }
        })).build();




        current = TranslateTransitionBuilder.create().fromX(0).toX(10).fromY(0).toY(10).node(me).duration(Duration.millis(4000)).onFinished(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                //startAnimation();
                if (RIGHT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    RIGHT_MOVEMENT.stop();
                    me.getChildren().setAll(human);
                }
                if (LEFT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    LEFT_MOVEMENT.stop();
                    me.getChildren().setAll(human);
                }
            }
        }).interpolator(Interpolator.LINEAR).build();
    }
    
    
    
    
    public void runTo(double toX, double toY) {
        if (current != null) {
            if (!current.statusProperty().get().toString().equals(Animation.Status.STOPPED.toString())) {
                if (RIGHT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    RIGHT_MOVEMENT.stop();
                    this.getChildren().setAll(human);
                }
                if (LEFT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    LEFT_MOVEMENT.stop();
                    this.getChildren().setAll(human);
                }
                current.stop();
            }
            
            

            
            
            double fromX=current.getNode().getTranslateX();
            double fromY=current.getNode().getTranslateY();

            double distance=Math.ceil(Math.sqrt(Math.pow(fromX-toX,2)+Math.pow(fromY-toY, 2))*1000)/1000; // Теорема Пифагора!!!
            //System.out.println(distance);
            if (current.getNode().getTranslateX() <= toX) {
                RIGHT_MOVEMENT.play();
            } else {
                LEFT_MOVEMENT.play();
            }
            Double time=Double.valueOf(Math.ceil(distance/SPEED*100)/100);
            Duration d=Duration.millis(time*1000);


If I shall uncomment this code and Duration d is not constant (it is some variable) teleportation of "human" will sometimes occurs. I have no found dependence between new coordinates toX and toY, duration (it was not zero) and teleportation effect. If Duration d is constant teleportation never occurs:

// current.setFromX(fromX);
// current.setFromY(fromY);
// current.setToX(toX);
// current.setToY(toY);
// current.setDuration(d);
            
If I am creating every time a new TranslateTransition object there is no any teleportation.
            
        current = TranslateTransitionBuilder.create().fromX(fromX).toX(toX).fromY(fromY).toY(toY).node(SELF).duration(d).onFinished(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                //startAnimation();
                if (RIGHT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    RIGHT_MOVEMENT.stop();
                    SELF.getChildren().setAll(human);
                }
                if (LEFT_MOVEMENT.statusProperty().get().compareTo(Animation.Status.RUNNING) == 0) {
                    LEFT_MOVEMENT.stop();
                    SELF.getChildren().setAll(human);
                }
            }
        }).interpolator(Interpolator.LINEAR).build();
            
            //System.out.println("fromX "+fromX+" fromY "+fromY+" toX "+toX+" toY "+toY+" time "+time+" distance "+distance+" duration "+d.toString());
            //System.out.println("fromX "+current.getFromX()+" fromY "+current.getFromY()+" toX "+current.getToX()+" toY "+current.getToY()+" time "+time+" distance "+distance+" duration "+current.getTotalDuration().toString());
            current.play();
        }
    }
}


This is a simple class. When user makes some mouse click on scene then calls:
        scene.setOnMousePressed(new EventHandler<MouseEvent>() {
            
            @Override
            public void handle(MouseEvent t) {
                human.runTo(t.getX(), t.getY());
                human2.runTo(t.getX()-70, t.getY());
                //System.out.println("KK");
            }
        });

Sometimes, when code is and duration is some variable but not a constant:

            current.setFromX(fromX);
            current.setFromY(fromY);
            current.setToX(toX);
            current.setToY(toY);
            current.setDuration(d);

human teleports into toX toY coordinates without any animation.
I think that this is a bug.