If you compile the QT example qt/Examples/Qt-6.4.2/widgets/mainwindows/menus, but add the following line to make the menu bar non-native (to avoid QTBUG-112272) 

void MainWindow::createMenus()

the the menu shows-up as expected, but only the first time. Subsequent touches on the menu item seem to popup the menu but its invisible. Still if you click on the space where the menu item must be - its triggered. Check the attached video.