Qml Shape as background button lead to color issue inside popup

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12
import QtQuick.Shapes 1.12

ApplicationWindow {
    id: window
    width: 640
    height: 480
    visible: true
    title: qsTr("qtbug86108")

    Column {
        anchors.centerIn: parent

        Button {
            text: "open popup"

            onClicked: popup.open();
        }

        Popup {
            id: popup
            anchors.centerIn: parent

            contentItem: Row {
                spacing: 24

                /*************************************
                * Using Qml Shape lead to a color bug
                * Steps to reproduice
                *
                * 1. open the popup
                * 2. clic on the left button
                * 3. close the popup by clicking outside
                * 4. open the popup again
                * 5. the button with the shape background is not in "blue" anymore
                *    but the text is still in white, and the checked property is still true
                *    The button is no usable anymore instead if we click on the second button
                *    to uncheck the first one
                */
                Button {
                    id: btnShape
                    text: "Shape background"
                    checkable: true
                    autoExclusive: true

                    palette.button: btnShape.checked ? "blue" : "lightgrey"

                    background: Shape {
                        id: shape
                        implicitWidth: 100
                        implicitHeight: 40
                        ShapePath {
                            fillColor: btnShape.palette.button
                            startX: 0
                            startY: 0
                            PathLine { x: shape.width; y: 0}
                            PathLine { x: shape.width; y: shape.height}
                            PathLine { x: 0; y: shape.height}
                            PathLine { x: 0; y: 0}
                        }
                    }
                }

                Button {
                    text: "Rectangle background"
                    checkable: true
                    autoExclusive: true
                }
            }
        }
    }
}