ADDITIONAL SYSTEM INFORMATION :
Windows 11, jdk-17.0.4.1+1

A DESCRIPTION OF THE PROBLEM :
With Windows set to a fractional scaling (125%), Graphics2D operations are done at inconsistent locations depending on the levels that get repainted. This happens for certain component heights, and certain component locations.
The result for the end-user is that a component is painted, then its state changes and is repainted but the bottom pixels are not updated, leaving ugly traces on screen.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Using the provided test case:
- Press "Repaint all" to repaint the whole UI, and the component gets painted in black.
- Press "Repaint component" to only repaint the component, and the component gets painted in white.

It is possible to increase the top border in case on your setup a different location is needed to trigger the bug.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The component should be completely white.
ACTUAL -
The component is white except for the bottom line that remained black.

See the error in this image: <link>

---------- BEGIN SOURCE ----------
package test.graphics2d;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Graphics2DTestOnHighDpi {

    private static int borderSize = 8;
    private static boolean isRepaintComponent;

public static void main(String[] args) {
JFrame frame = new JFrame("Graphics2D Test with fractional scaling");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
JPanel northPane = new JPanel(new FlowLayout());
northPane.setBorder(BorderFactory.createEmptyBorder(borderSize, 0, 0, 0));
        JPanel componentContainer = new JPanel();
        componentContainer.setLayout(new BoxLayout(componentContainer, BoxLayout.LINE_AXIS));
        JComponent component = new JComponent() {
            @Override
            protected void paintComponent(Graphics g) {
                g.setColor(isRepaintComponent? Color.WHITE: Color.BLACK);
                g.fillRect(0, 0, getWidth(), getHeight());
                isRepaintComponent = false;
            }
        };
        component.setPreferredSize(new Dimension(50, 32));
        componentContainer.add(component);
northPane.add(componentContainer, BorderLayout.CENTER);
        contentPane.add(northPane, BorderLayout.NORTH);
        JPanel southPane = new JPanel(new FlowLayout());
        JButton increaseBorderButton = new JButton("Increase top margin");
        increaseBorderButton.addActionListener((ae) -> northPane.setBorder(BorderFactory.createEmptyBorder(++borderSize, 0, 0, 0)));
        southPane.add(increaseBorderButton);
        JLabel repaintComponentButton = new JLabel("Repaint Component");
        repaintComponentButton.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        repaintComponentButton.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                isRepaintComponent = true;
                component.repaint();
            }
        });
        southPane.add(repaintComponentButton);
        JLabel repaintAllButton = new JLabel("Repaint all");
        repaintAllButton.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        repaintAllButton.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                frame.repaint();
            }
        });
        southPane.add(repaintAllButton);
        contentPane.add(southPane, BorderLayout.SOUTH);
frame.setSize(400, 300);
frame.setVisible(true);
}

}

---------- END SOURCE ----------

FREQUENCY : always