Assigning attached property to Connections.target results in error

import QtQuick 2.10
import QtQuick.Layouts 1.1

Item {
    id: root

    Rectangle {
        id: rect
        width: 50
        height: 50
        color: "red"
        Layout.preferredWidth: 50

        MouseArea {
            anchors.fill: parent
            onClicked: {
                if (rect.Layout) {
                    console.log(rect.Layout)
                    cnLayout.target = rect.Layout
                    cnLayout.target = rect.Component // The same problem.
                    // Prints:
                    // qml: QQuickLayoutAttached(0x7fd0d6e5ad20)
                    // file:///Users/uzumcuf/Desktop/QMLBug/main.qml|20| Error: Cannot assign null to QObject*
                }
            }
        }
    }

    Connections {
        id: cnLayout
        ignoreUnknownSignals: true
    }
}