Failure to decode ETC2 texture (*.pkm file) if downloaded over HTTP

import QtQuick 2.15
import QtQuick.Window 2.15

Window {
    width: 640
    height: 480
    visible: true

    Column {
        Image {
            width: 100
            height: 100
            source: "qrc:/youtube.pkm"
        }
        Image {
            width: 100
            height: 100
            source: "http://127.0.0.1:4000/images/youtube.pkm"
        }
    }
}