Using WinTab leads to TWO MouseButtonPress events being synthesize

#include <QtGui/private/qguiapplication_p.h>
#include <QtGui/qpa/qplatformintegration.h>
#include <QDebug>
#include <QApplication>
#include <QPushButton>
#include <QPainter>
#include <QTabletEvent>
#include <QMainWindow>
#include <QMenu>
using QWindowsApplication = QNativeInterface::Private::QWindowsApplication;
bool is_wintab_enabled(){
    auto nativeWindowsApp = dynamic_cast<QWindowsApplication *>(QGuiApplicationPrivate::platformIntegration());
    return nativeWindowsApp && nativeWindowsApp->isWinTabEnabled();
}
void enable_wintab(bool state){
    qDebug() << "Set wintab status to:" << state << "Current: " << is_wintab_enabled();
    if (auto nativeWindowsApp = dynamic_cast<QWindowsApplication *>(QGuiApplicationPrivate::platformIntegration()))
        nativeWindowsApp->setWinTabEnabled(state);
    qDebug() << "Post set wintab status to:" << state << "Current: " << is_wintab_enabled();
}

class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent=nullptr) : QMainWindow(parent) {
        setMinimumSize(500, 500);
        // Simple state issue demonstration.
        // Ti all boils down to this issue
        QPushButton *btn = new QPushButton("Click me", this);
        connect(btn, &QPushButton::pressed, this, [this](){
            state = !state;
            qDebug() << "Button pressed";
            update();
        });
        // Demonstrating the issue with a simple menu
        QPushButton *menuButton = new QPushButton("Show menu", this);
        QMenu *menu = new QMenu(menuButton);
        menu->addMenu("TEst 1");
        menu->addMenu("TEst 2");
        menu->addMenu("TEst 3");
        menuButton->setMenu(menu);
        menuButton->move(0, 30);
    }
protected:
    bool state = false;
    void mousePressEvent(QMouseEvent *event) override {
        // Just to demonstrate the two press events we receive
        QMainWindow::mousePressEvent(event);
        qDebug() << "Mouse pressed" << event->pointingDevice()->pointerType();
    }
    void mouseReleaseEvent(QMouseEvent *event) override {
        // We do NOT get two Release events
        QMainWindow::mouseReleaseEvent(event);
        qDebug() << "Mouse released";
    }
    void paintEvent(QPaintEvent *event) override {
        // Just draw a different background based on state
        QPainter p(this);
        p.fillRect(rect(), state ? Qt::red : Qt::black);
    }

};
class WinTabClickWorkaround : public QObject{
    Q_OBJECT
public:
    bool eventFilter(QObject *watched, QEvent *event) override{
        if(event->type() == QEvent::MouseButtonPress){
            QMouseEvent *evt = static_cast<QMouseEvent*>(event);
            if(evt->pointingDevice()->pointerType() == QPointingDevice::PointerType::Pen || evt->pointingDevice()->pointerType() == QPointingDevice::PointerType::Eraser){
                assert(is_wintab_enabled());  // in my experience Windows Ink synthetised mouse events are never this type
                qDebug() << "Supress mouse";
                return true;
            }
        }
        return QObject::eventFilter(watched, event);
    }
};
#include "main.moc"
int main(int argc, char *argv[])
{
    bool USE_WINTAB = true;
    bool USE_WORKAROUND = false;

    QApplication a(argc, argv);
    if(USE_WORKAROUND){
        a.installEventFilter(new WinTabClickWorkaround());
    }
    MainWindow w;
    if(USE_WINTAB){
        enable_wintab(true);
    }
    w.show();
    return a.exec();
}