Reparenting the ShaderEffect source item has undesired side effects

import QtQuick 2.0

Rectangle {
    id: root
    width: 300
    height: 300

    Text {
        id: text
        anchors.centerIn: parent
        font.pixelSize: 120
        font.family: "Times"
        color: "green"
        text: "Qt"
    }

    Timer {
        interval: 500
        running: true
        repeat: true
        onTriggered: {
            text.parent = (text.parent ? null : root);
            console.log(text.parent);
        }
    }

    ShaderEffect {
        anchors.fill: parent
        property variant source: ShaderEffectSource {
            sourceItem: text
            hideSource: true
            smooth: true
        }
    }
}