WASM: QNetworkRequest, parameters encoded in URL are ignored

The attached example calls "http://urlecho.appspot.com/echo?body=HelloWorld" once the button "Go" is clicked. The result should be "HelloWorld".
If I build the example for Linux it does just that.

If I build the example with emscripten and run it in Firefox the get request returns "None".

I had a look at the implementation in the file "Qt/5.12.0/Src/qtbase/src/network/access/qnetworkreplywasmimpl.cpp".
In the line 321 it strips the request url from its parameters:

    if (request.url().hasQuery()) { //strip query from url
        extraDataString = request.url().query(QUrl::FullyEncoded);
        QString urlStr = request.url().toString();
        url.setUrl(urlStr.left(urlStr.indexOf("?")));
    } else {
        url = request.url();
    }

For testing I removed this and rebuilt Qt and the example started working in the Browser as well.