Qt Gamepad doesn't work with many gamepads and doesn't react to some buttons

I tried to launch this example to learn how does QtGamepad work.

It should detect all gamepads and print events of all of them.

It thinks that only one gamepad has been connected, but I have connected two gamepads.

    auto gamepads = QGamepadManager::instance()->connectedGamepads();
    qDebug() << "Number of gamepads:" << gamepads.size();

prints "Number of gamepads: 1"

If I press any button on one of them, it prints a message that button was pressed, but shows the same device ID.

And Qt doesn't react on my gamepad buttons 2 and 5 (as just numbers them).