QtQuick Shapes rendering is broken with layers and NVIDIA vendor extensions enabled

import QtQuick 2.8
import QtQuick.Window 2.2
import QtQuick.Shapes 1.0

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

    Item {
        anchors.fill: parent
        layer.enabled: true
        Shape {
            width: 200
            height: 150
            anchors.centerIn: parent
            ShapePath {
                strokeWidth: 4
                strokeColor: "red"
                fillGradient: LinearGradient {
                    x1: 20; y1: 20
                    x2: 180; y2: 130
                    GradientStop { position: 0; color: "blue" }
                    GradientStop { position: 0.2; color: "green" }
                    GradientStop { position: 0.4; color: "red" }
                    GradientStop { position: 0.6; color: "yellow" }
                    GradientStop { position: 1; color: "cyan" }
                }
                strokeStyle: ShapePath.DashLine
                dashPattern: [ 1, 4 ]
                startX: 20; startY: 20
                PathLine { x: 180; y: 130 }
                PathLine { x: 20; y: 130 }
                PathLine { x: 20; y: 20 }
            }
        }
    }
}