StackView: Orientation change sometimes fails

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3
import QtQuick.Controls.Material 2.0
import QtGraphicalEffects 1.0

// Orientation Bug
ApplicationWindow {
    id: appWindow
    visible: true
    title: "ekkes dummi app"
    width: 411
    height: 683
    Material.primary: Material.Teal
    Material.accent: Material.DeepOrange

    StackView {
        id: rootPane
        focus: true
        anchors.top: parent.top
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.bottom: parent.bottom

        initialItem:
            Flickable {
                id: flickable
                contentHeight: pane.implicitHeight
                // contentWidth: appWindow.width

                Pane {
                    id: pane
                    anchors.fill: parent
                    ColumnLayout {
                        Layout.fillWidth: true
                        anchors.left: parent.left
                        anchors.right: parent.right
                        anchors.leftMargin: 12
                        anchors.rightMargin: 24

                        RowLayout {
                            Label {
                                text: "Open in Portrait\nPush Button\nresize to Landscape\nGo Back\nResize to Portrait\npartly outside visible area"
                            }
                        }

                        RowLayout {
                            Button {
                                text: "Push this Button to Test"
                                onClicked: {
                                    rootPane.pushSomething()
                                }
                            }
                        }

                        RowLayout {
                            Layout.fillWidth: true
                            spacing: 24
                            Item {
                                width: 12
                            }

                            Item {
                                Layout.preferredWidth : 1
                                Layout.fillWidth: true
                                Button {
                                    id: buttonCheckIn
                                    focusPolicy: Qt.NoFocus
                                    contentItem:
                                        Item {
                                        Text {
                                            anchors.centerIn: parent
                                            text: "CheckIn"
                                            color: "white"
                                        }
                                    }
                                    background:
                                        Rectangle {
                                        implicitWidth: 100
                                        implicitHeight: 100
                                        color: "green"
                                        radius: width / 2
                                    }
                                    onClicked: {
                                        //
                                    }
                                } // buttonCheckIn
                            } // greenButton Item

                            Item {
                                Layout.preferredWidth : 1
                                Layout.fillWidth: true
                                Button {
                                    id: buttonCheckOut
                                    focusPolicy: Qt.NoFocus
                                    contentItem:
                                        Item {
                                        Text {
                                            anchors.centerIn: parent
                                            text: "CheckOut"
                                            color: "white"
                                        }
                                    }
                                    background:
                                        Rectangle {
                                        implicitWidth: 100
                                        implicitHeight: 100
                                        color: "red"
                                        radius: width / 2
                                    }
                                    onClicked: {
                                        //
                                    }
                                } // buttonCheckOut
                            } // redButton Item

                            // Uncomment fakeItem:
                            // now resizing works in Portrait and Landscape as expected
//                            Item {
//                                id: fakeItem
//                                anchors.right: parent.right
//                                width: 6
//                                height: 10
//                                Rectangle {
//                                    color: "blue"
//                                    anchors.fill: parent
//                                }
//                            } // fakeItem


                        } // row layout


                    } // column layout

                } // pane

            } // flickable

        function pushSomething() {
            rootPane.push(aComponent)
        }
        Component {
            id: aComponent
            Page {
                ColumnLayout {
                    Label {
                        text: "something"
                    }
                    Button {
                        text: "go back"
                        onClicked: {
                            rootPane.pop()
                        }
                    }
                }


            }
        } // aComponent

    } // rootPane

} // appwindow