QOpenGLWidget and QSurfaceFormat::setSamples are not really good friends

#include <QApplication>
#include <QSurfaceFormat>
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QKeyEvent>
#include <QtDebug>

/**
 * @brief The MyOpenGLWidget class
 * Simple example to show that there is a bug with QOpenGLWidget and multisample
 * When the user hits A it displays a rectangle until the key is released
 * If no sample value is set to QSurfaceFormat, it works properly
 * If a value is set the behaviour is changed.
 * When the key is released it displays the rectangle and the rectangle is hidden when the key is pressed
 */

class MyOpenGLWidget : public QOpenGLWidget, public QOpenGLFunctions
{
public:

    MyOpenGLWidget(QWidget *parent) : QOpenGLWidget(parent){
        setMouseTracking(true);
        setFocusPolicy(Qt::StrongFocus);
        setAutoFillBackground(false);
    }
    ~MyOpenGLWidget(){

    }

    void resizeGL(int, int){

    }

    void paintGL(){
        glClearColor(0.5, 0.5, 0.5, 1.0);
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        glEnable(GL_DEPTH_TEST);

        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, width(), 0, height(), -1, 1);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();


        if (m_draw){
            glColor3f(0, 1, 0);
            glBegin(GL_QUADS);
            glTexCoord2f(0, 0);
            glVertex2f(200, 200);
            glTexCoord2f(1, 0);
            glVertex2f(width()-200, 200);
            glTexCoord2f(1, 1);
            glVertex2f(width()-200, height()-200);
            glTexCoord2f(0, 1);
            glVertex2f(200, height() - 200);
            glEnd();
        }
    }

    void initializeGL(){
        initializeOpenGLFunctions();
    }

    void keyReleaseEvent(QKeyEvent* e){
        if (e->key() == Qt::Key_A){
            m_draw = false;
            update();
        }


    }
    void keyPressEvent(QKeyEvent* e){
        if (e->isAutoRepeat())
            return ;

        if (e->key() == Qt::Key_A){
            m_draw = true;
            update();
        }
    }

protected:

    bool m_draw;
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QSurfaceFormat format;
    format.setVersion(2, 0);
    format.setProfile(QSurfaceFormat::NoProfile);
    format.setDepthBufferSize(24);
    format.setSamples(2); // <----- Bug here if we activate this line
    format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
    QSurfaceFormat::setDefaultFormat(format);

    MyOpenGLWidget w(0);
    w.showMaximized();
    return a.exec();
}