Setting Connections.target to null not always disconnects the target

import QtQuick 2.0

Item {
    MouseArea {
        id: mouse_area
        anchors.fill: parent
        Connections {
            id: connections
            // target: mouse_area // Testcase works if this line is uncommented
            onPressedChanged: {
                console.log("pressed changed")
            }
        }
        onClicked: {
            console.log("connections target", connections.target, mouse_area)
            connections.target = null
            console.log("connections target", connections.target, mouse_area)
        }
    }
}