winId() return wrong hwnd when window contains a QWebEngine widget

To reproduce:

#include <QtWebEngineWidgets/QWebEngineView>
 
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) 
{
       ui.setupUi(this);
       QWebEngineView* engine = new QWebEngineView(this);

       HWND hwnd = (HWND)this->winId();
       qDebug() << "\nhwnd: " << hwnd << "\n";
}

The hwnd returned by windId() isn't the same of the main window.

When i search for any window which the given id nothing is found, which means the window doesnt exist anymore.

Commenting the line QWebEngineView* engine = new QWebEngineView(this); it does return the hwnd of the main window correctly.

Im not sure if this can be called a bug, but how i can know the main window hwnd in this case?