Videos keep playing even after calling QWebEngineView::close()

If a video is started in a QWebEnginePage instance and sometime later it si closed, the audio keeps playing, until the process is quit. Minimal script to reproduce (this is in PyQt 5.7 should be trivial to port to C++).

from PyQt5.Qt import (
    QApplication, QWebEnginePage, QWebEngineProfile, QWebEngineView, QUrl, QTimer
)

app = QApplication([])
w2 = QWebEngineView()
w2.load(QUrl('https://google.com'))
w2.show()
w = QWebEngineView()
w.load(QUrl('https://www.youtube.com/watch?v=al2DFQEZl4M'))
w.show()

app.exec_()

Run the script, it will create two windows, one of which is playing a youtube video. After the video starts, close that window. The audio keeps on playing even though the window is closed.