Error on second dinamicaly created object(QCoreApplication::postEvent: Unexpected null receiver) if this object have SoundEffect.

[alex_lip]

I create some object dinamicaly

function createMobs() {
    var x1,y1;
    var component = Qt.createComponent("../content/Zobie1.qml");
    for (var i=0; i<5; i++) {
        x1=Math.ceil(Math.random() * i_tem.width);
        y1=Math.ceil(Math.random() * i_tem.height/3*2);
        var object = component.createObject(i_tem,{"x": x1, "y": y1, "opacity" :1 });
        object.objectName="zomb"+zombi_count.toString();
        console.log(object.objectName);
        zombi_count ++ ;
    }
}

File Zobie1.qml have SoundEffect

    SoundEffect {
        id: playSoundZobie
        source: "../sfx/ZombieWalk.wav"
        loops: SoundEffect.Infinite
        volume : 0.3

    }

First object created good, but from second I see error - QCoreApplication::postEvent: Unexpected null receiver - But object create normal and soundeffect work excelent. if I remove SoundEffect - no errors.
In principle, everything works - but why does the error appear?