PageIndicator with pragma ComponentBehavior: Bound causes QQmlContext: Cannot set property on internal context.

pragma ComponentBehavior: Bound
import QtQuick.Controls as QQC
import QtQuick

Window {
    height: 100
    visible: true
    width: 100

    QQC.PageIndicator {
        id: control

        anchors.fill: parent
        count: 3
        interactive: true

        delegate: Rectangle {
            required property int index

            color: index === control.currentIndex ? "red" : "grey"
            implicitHeight: 18
            implicitWidth: 18
            radius: width / 2
        }
    }
}

QQmlContext: Cannot set property on internal context.