Can't access .SF NS Text font from QWebEngineView on Mac OSX El capitan

Hi, it's my first bug report for Qt.

I'm not even sure I should post here. I encounter a problem while developing a software with PyQt, and I suspect my bug comes from Qt.

I set the default font of my app like that:

font = QtGui.QFont()
font.setStyleHint(QtGui.QFont.System)
font.setPointSize(self.styles.FONT_SIZE)
font.setStyleStrategy(QtGui.QFont.PreferAntialias)
QtWidgets.qApp.setFont(font)

Basically, I let Qt and the system choose the font. Later, I try to set the font of a QWebEngine view:

self.settings().setFontFamily(QtWebEngineWidgets.QWebEngineSettings.StandardFont, self.parent.font().family())

Basically, I use the default font of the app to set the StandardFont of the QWebEngineView.

However, on Mac OSX El capitan, the app's default font is .SF NS Text. But I can't use this font in QWebEngineView. I can use any other font (like Helvetica), but not this one. It's probably because .SF NS Text is not user accessible.

I don't want to specify a default font for my app, because it's cross platform and I don't want to mess with the OS' font style.

A solution would be to avoid .SF NS Text globally. But substitution does not work:

QFont::insertSubstitution(".SF NS Text", "Helvetica");

Could you give me a hand ?

EDIT: I think it might be related to https://bugreports.qt.io/browse/QTBUG-56160. Should I wait for version 5.7.1 ?