QOpenGLWidget renders incorrectly when launching a child QWebEngineView

When an QOpenGLWidget opens a child Dialog having QWebEngineView top level window flickers/disappears for tiny second and appears again.

Attached example shows this, In this example there is a QMainWindow that renders a QOpenGLWidget, and a button to launch a dialog containing a QWebEngineView. When the button is clicked, the mainwindow briefly closes before the dialog and MainWindow both reappear.

The QWebEngineView appears to be correct with the webpage correctly rendered and loaded, however the QOpenGLWidget is now rendering itself as a reflection of the mainwindow (e.g. it is rendering the Dialog launch button as upside down).

Building this with Qt6.5.8 is correct.