QShortcut not work on Mac if keyboard layout switched to russian

QShortcuts in Mac OS X works very strange way with no-english keyboard layout (in windows and linux it works fine).

1. After application start, change keyboard layout to russian - shortcuts not work.
2. After application start, check shortcut at english keyboard layout - shortcuts work. Change layout to russian - shortcuts still work. (!!!)
3. After application start, change keyboard layout to russian - shortcuts not work. Change layout to english - shortcuts still not work. (!!!???)
4. If we add QAction with shortcut to application menu - shortcut work with any keyboard layout.

Minimal example:

#include <QApplication>
#include <QLabel>
#include <QShortcut>
#include <QTime>

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

   QLabel* label = new QLabel(QTime::currentTime().toString("hh:mm:ss:zzz"));
   QShortcut* shortcut = new QShortcut(QKeySequence("Ctrl+U"), label);
   QObject::connect(shortcut, &QShortcut::activated, [=] {
      label->setText(QTime::currentTime().toString("hh:mm:ss:zzz"));
   });

   label->show();

   return a.exec();
}