Unsolved Memory leak - dynamic loader - canvas

[Prochy]

Hi.

I use a loader for a dynamic load QML file. In the QML file, I use Canvas but when I'm changing a source file of the Loader, memory leak occurs. How do I can to prevent memory leaks?

I use Qt v.5.8 with mingw53_32 on Windows 7, on Linux is the same problem.

Here is a simple example, which occurs the memory leak.
http://www.filedropper.com/untitled2_1

Or here the code:
main.cpp

TestTimer test;
    QTimer *timer = new QTimer(&test);
    QObject::connect(timer,SIGNAL(timeout()),&test,SLOT(changeFile()));
    timer->start(20);
    _myComponent->loadUrl(QUrl(QStringLiteral("qrc:/main.qml")));
    _engine->rootContext()->setContextProperty("test",&test);
    QObject* _myComponentObj = _myComponent->create();
    return app.exec();

testtimer.cpp

QUrl TestTimer::urlFile(){
    return _urlFile;
}

void TestTimer::changeFile(){
    if(page1)
        _urlFile=QUrl(QLatin1String("qrc:/Page2.qml"));
    else
        _urlFile=QUrl(QLatin1String("qrc:/Page1.qml"));
    page1=!page1;
    emit urlFileChanged();
}

main.qml

    Loader{
        source: test.urlFile
    }

Page1.qml and Page2.qml

Canvas{
    property int borderSize:1
    height:100;width:100
    onPaint: {
        var centerLine = borderSize/2;
        var ctx = getContext("2d");
        ctx.lineCap="square";
        //ctx.translate(0.5, 0.5);
        ctx.strokeStyle = "red";
        ctx.lineWidth=borderSize;
        ctx.beginPath();
        ctx.lineTo(centerLine,height-borderSize+centerLine);
        ctx.lineTo(centerLine,borderSize/2);
        ctx.lineTo(width-borderSize+centerLine,borderSize/2);
        ctx.stroke();
        ctx.beginPath();
        ctx.moveTo(centerLine,height-borderSize+centerLine);
        ctx.lineTo(width-borderSize+centerLine,height-borderSize+centerLine);
        ctx.lineTo(width-borderSize+centerLine,centerLine);
        ctx.stroke();
    }
}

Thank you for help