isRotating() returns false when QTransform is rotated exactly 180 degrees

void MainWindow::paintEvent(QPaintEvent *)
{
    QPainter paint(this);

    QTransform transform;
    transform.rotate(180.0);  // test with 180.0 degrees and then with 180.01 degrees

    if ( transform.isRotating() )
    {
    qDebug() << "isRotating():" << transform.isRotating();
    }
    else
    {
    qDebug() << "isRotating():" << transform.isRotating();
    }

    paint.drawPixmap(0,0, QPixmap::fromImage(QImage(QString(":/example.jpg")).transformed(transform)));
}