节点（例如 ImageView s） 在任何场景图中只能出现一次。您正在尝试使用每个 ImageView 在根窗格中两次；基本上，这里发生的是第二次添加 ImageView 到根（通过 Tile )，它将从第一个磁贴中移除并放置在第二个磁贴中。如果你点击 Tile 与第一次添加图像相对应，使用第二次添加图像时的坐标显示图像。
相反，您可以创建 Image s、 并使用每个 Image 两次在两个不同的 ImageView s。这样的方法应该有用：

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.util.Duration;

import java.util.*;

public class Main extends Application {
    private int num_of_pairs = 8;
    private int num_per_row = 4;

    Tile selected = null;
    private int clickCount=2;

    @Override
    public void start(Stage primaryStage) throws Exception {

        primaryStage.setTitle("Hello World");

        Pane root = new Pane();

        ArrayList<Tile> tiles = new ArrayList<>();

        // Note array changed to Image:
        Image[] puzz=new Image[num_of_pairs];

        for(int i=0;i< puzz.length;i++){
            puzz[i]= new Image("image.jpeg");
        }

        for (int i = 0; i < num_of_pairs; i++) {

            // Create two *different* ImageViews for each Image:

            ImageView first = new ImageView(puzz[i]);
            first.setFitHeight(110);
            first.setFitWidth(110);

            ImageView second = new ImageView(puzz[i]);
            second.setFitHeight(110);
            second.setFitWidth(110);

            tiles.add(new Tile(first));
            tiles.add(new Tile(second));

        }

        Collections.shuffle(tiles);

        for (int i = 0; i < tiles.size(); i++) {

            Tile tile = tiles.get(i);

            tile.setTranslateX(120 * (i % num_per_row));
            tile.setTranslateY(120 * (i / num_per_row));

            System.out.println(120*(i%num_per_row));
            System.out.println(120*(i/num_per_row));

            root.getChildren().add(tile);

        }

        primaryStage.setScene(new Scene(root, 800, 550));
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

    class Tile extends StackPane {

        ImageView image;

        Tile(ImageView image) {
            this.image=image;

            Rectangle border = new Rectangle(120, 120);

            border.setFill(null);

            border.setStroke(Color.BLACK);

            getChildren().addAll(this.image,border);

            setOnMouseClicked(this::handleMouseClick);

            close();
        }

        public void handleMouseClick(MouseEvent event){

                if (isOpen() || clickCount==0)
                    return;
                clickCount--;
                if (selected == null) {
                    selected = this;
                    open(() ->{});
                }else{
                    open(() -> {
                        if(!hasSameValue(selected)){
                            selected.close();
                            this.close();
                        }
                        selected=null;
                        clickCount=2;
                    });
                }

            }

        public boolean isOpen() {
            return image.getOpacity() == 1;
        }

        public void close() {
            FadeTransition ft = new FadeTransition(Duration.seconds(0.5), image);
            ft.setToValue(0);
            ft.play();
        }

        public void open(Runnable action) {
            FadeTransition ft = new FadeTransition(Duration.seconds(0.5), image);
            ft.setToValue(1);
            ft.setOnFinished(e -> action.run());
            ft.play();
        }

        public boolean hasSameValue(Tile other) {
            return image.getImage().equals(other.image.getImage());
        }

    }
}