Mixing old and new Connections syntax has weird effect

qrc:/qt/qml/untitled19/Main.qml:15:5: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
qml: onReleased QQuickKeyEvent(0x556b299407d8)
qml: onReleased QQuickKeyEvent(0x556b299407d8)
qml: onReleased QQuickKeyEvent(0x556b299407d8)
...

import QtQuick

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    Rectangle {
        id: rectangle
        anchors.fill: parent
        Component.onCompleted: rectangle.forceActiveFocus()
    }

    Connections {
        target: rectangle.Keys

        function onPressed(event) {
            console.log("function onPressed", event)
        }
        //function onReleased(event)  {
        //    console.log("function onReleased", event)
        //}

        onReleased: function(event) {
            console.log("onReleased", event)
        }
    }
}