Weird issue with WebView and Whatsapp web

[tubbadu]

Hello! I'm trying to display the whatsapp web website (web.whatsapp.com) in a webview element, Qt6. To do so, I changed the user agent, like this:

import QtQuick
import QtQuick.Controls
import QtWebEngine
import QtWebView

ApplicationWindow {
    visible: true
    width: 800
    height: 600

    WebView {
        id: webView
        anchors.fill: parent
        httpUserAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36"

        onLoadingChanged: {
            deleteAllCookies()
            httpUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36"
        }

        Component.onCompleted: {
            // Load example.com
            webView.url = "https://web.whatsapp.com/";
           // webView.url = "https://www.whatismybrowser.com/";
        }
    }
}

and then I run it with

qml6 main.qml

the strange thing is that it works until the page is reloaded. right after being run, it displays the QR code, and you can log in and view and send messages perfectly. But if I right click on the page and hit "reload", it imediately displays the "you must use Chrome 60+" message. I tried loading https://www.whatismybrowser.com/ to show my useragent, and even after reloading it still is the one I set. Why is whatsapp behaving like this? how can I solve this?