Object.keys(any "delegate" property) returns the key "loadUrl" twice

import QtQuick 2.12
import QtQuick.Window 2.12

Window {
    visible: true

    Component {
        id: component
        Text {
            text: "foo"
        }
    }
    
    Component.onCompleted: {
        print("keys(component) =", Object.keys(component))
        // [objectName,progress,status,url,objectNameChanged,statusChanged,progressChanged,loadUrl,loadUrl,setData,errorString,createObject,incubateObject]
    }
}