ToolTip style widget is moved up 20 pixels when calling show()

// Copyright (C) 2024 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include <QApplication>
#include <QHelpEvent>
#include <QLabel>
#include <QVBoxLayout>
#include <QWidget>

class MyWidget : public QWidget
{
public:
    bool event(QEvent *e) override
    {
        if (e->type() == QEvent::ToolTip) {
            if (m_tip) {
                delete m_tip;
            }
            m_tip = new QWidget(this);
            m_tip->setWindowFlags(Qt::ToolTip);
            auto layout = new QVBoxLayout;
            layout->setContentsMargins(0, 0, 0, 0);
            m_tip->setLayout(layout);
            layout->addWidget(new QLabel("foo"));
            // The following three lines lead to the call of show() moving the widget
            // 20 pixels up.
            // Commenting any of these lines avoids the up-movement behavior of show().
            layout->addWidget(new QLabel("bar"));
            layout->setSizeConstraint(QLayout::SetFixedSize);
            m_tip->adjustSize();

            m_tip->move(static_cast<QHelpEvent *>(e)->globalPos());
            qDebug() << "before:" << m_tip->pos();
            m_tip->show();
            qDebug() << "after:" << m_tip->pos();
            return true;
        }
        return QWidget::event(e);
    }
    QWidget *m_tip = nullptr;
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    MyWidget w;
    w.show();

    return a.exec();
}