Qt fails to set usesRhiFlush in certain widget hierarchy

#include <QtWidgets/QApplication>
#include <QtWidgets/QWidget>
#include <QtOpenGLWidgets/QOpenGLWidget>
#include <QtGui/QOpenGLFunctions>
#include <QtGui/QWindow>

class MyRhiWidget : public QOpenGLWidget, protected QOpenGLFunctions
{
	QColor m_bgClr;

public:
	MyRhiWidget(QColor bgClr, QWidget* parent)
		: QOpenGLWidget(parent)
		, m_bgClr(bgClr)
	{
	}

	void initializeGL() override
	{
		initializeOpenGLFunctions();
	}

	void paintGL() override
	{
		glClearColor(m_bgClr.redF(), m_bgClr.greenF(), m_bgClr.blueF(), 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);
	}
};

int main(int argc, char** argv)
{
	QApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
	QApplication app(argc, argv);

	// tlw: red.
	QWidget tlw;
	tlw.resize(640, 480);
	tlw.setStyleSheet("QWidget { background-color: red; }");

	// native: blue.
	QWidget native(&tlw);
	native.setGeometry(0, 240, 640, 240);
	native.setStyleSheet("QWidget { background-color: blue; }");
	native.winId();

	// rhi child of native: yellow
	MyRhiWidget rhi2(Qt::yellow, &native);
	rhi2.setGeometry(0, 0, 640, 240);

	// With https://codereview.qt-project.org/c/qt/qtbase/+/541664, the surface format will changes to:
	//   tlw: raster
	//   native: raster -> d3d11/metal/opengl (opengl here due to QOpenGLWidget for convenience).
	assert(tlw.windowHandle()->surfaceType() == QSurface::RasterSurface);
	assert(native.windowHandle()->surfaceType() == QSurface::OpenGLSurface);

	// rhi child of tlw: green
	MyRhiWidget rhi1(Qt::green, &tlw);
	rhi1.setGeometry(0, 0, 640, 240);

	// The surface format of tlw is expected to change to opengl.
	// Got:
	//   Black
	//   Yellow
	// Fail: assert(tlw.windowHandle()->surfaceType() == QSurface::OpenGLSurface);

	tlw.show();
	return app.exec();
}