Primary orientation isn't updated after rotating screen

//demo

#include <QApplication>
#include <QDebug>
#include <QTimer>
#include <QScreen>

int main(int argc,char* argv[])
{
    if (!qgetenv("QT_SCREEN_SCALE_FACTORS").isEmpty()) {
        qDebug() << qgetenv("QT_SCREEN_SCALE_FACTORS");
        qunsetenv("QT_SCREEN_SCALE_FACTORS");
    }
    QApplication a(argc,argv);
    QTimer t;
    t.connect(&t,&QTimer::timeout,[](){
        auto screen = qApp->primaryScreen();
        auto orientation = screen->primaryOrientation();
        qDebug() << "primaryOrientation" << orientation;
    });
    t.start(500);
    return a.exec();
}