QMessageBox components get skipped by Windows Narrator

Start Windows Narrator ([Ctrl][Win][Enter]), then build and run this code:

#include <QApplication>
#include <QPushButton>
#include <QMessageBox>

static void launchDialog()
{
    QMessageBox::warning(nullptr,
        qApp->applicationName(),
        "This is dangerous. Proceed?",
        QMessageBox::Yes | QMessageBox::No);
}

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

    launchDialog();

    QPushButton button("Click me");
    button.show();
    QObject::connect(&button, &QPushButton::clicked, &launchDialog);

    return a.exec();
}

What happens

1. At startup, the first QMessageBox pops up. Windows Narrator reads out the body text ("This is dangerous. Proceed?") then focusses on the QButtonGroup and says "Group". It does not read the text of the button that receives focus ("Yes").
2. When you click "OK" the QMessageBox is dismissed and the "Click Me" button appears.
3. When you click "Click Me", another instance of the QMessageBox appears. Windows Narrator reads the button with focus ("Yes"), then stops. It does not read the QMessageBox body text and it doesn't say "Group".

What should happen instead

• In Step #1, Windows Narrator should read "Yes" at the end.
• In Step #3, Windows Narrator should read the body text at the start.