ADDITIONAL SYSTEM INFORMATION :
Tested on Windows 11 with JDK 17.0.2 and JavaFX 17.0.2

A DESCRIPTION OF THE PROBLEM :
The calculated bounds of javafx.scene.shape.Polygon can be extremely overgrown. The issue appears when the shape is scaled up by a large value. After digging down in the JavaFX code, I believe the issue comes from an arbitrary augmentation of the shape bounding box here:
https://github.com/openjdk/jfx/blob/master/modules/javafx.graphics/src/main/java/javafx/scene/shape/Shape.java#L1124-L1127
It seems that the "0.5" augmentation assumes that no scale is applied to the shape.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
The example source code can be run to demonstrate the issue. The example shows in a 2D view, a blue polygon, surrounded by a black rectangle that represents the computed bounds.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The bounds should be the tightest bounding box, i.e. touching the polygon left vertices.
ACTUAL -
The bounds is drastically bigger than the polygon.

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Rectangle;
import javafx.scene.transform.Scale;
import javafx.stage.Stage;

public class PolygonBoundsApp extends Application
{
   @Override
   public void start(Stage stage) throws Exception
   {
      StackPane root = new StackPane();
      Scene sc = new Scene(root, 600, 600);
      stage.setScene(sc);
      stage.show();

      int scale = 150;

      Polygon polygon = new Polygon(-0.1, -0.1, 0.1, -0.08, 0.1, 0.08, -0.1, 0.1);
      polygon.strokeProperty().set(Color.CADETBLUE);
      polygon.setStrokeWidth(1.5 / scale);
      polygon.fillProperty().set(null);

      Rectangle polygonBounds = new Rectangle();
      polygonBounds.setX(polygon.getBoundsInLocal().getMinX());
      polygonBounds.setY(polygon.getBoundsInLocal().getMinY());
      polygonBounds.setWidth(polygon.getBoundsInLocal().getWidth());
      polygonBounds.setHeight(polygon.getBoundsInLocal().getHeight());
      polygonBounds.strokeProperty().set(Color.BLACK);
      polygonBounds.setStrokeWidth(1.5 / scale);
      polygonBounds.fillProperty().set(null);

      Group group = new Group();
      group.getTransforms().add(new Scale(scale, scale));
      group.getChildren().add(polygon);
      group.getChildren().add(polygonBounds);
      root.getChildren().add(group);
   }

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

CUSTOMER SUBMITTED WORKAROUND :
I have not found a workaround for this issue at the moment.

FREQUENCY : always