Rendering of text with embedded fonts above a certain size broken

Attached test.html and Ubuntu-R.ttf files demonstrate the problem. Text at 12pt is rendered, same text at 40pt is not rendered. If the system version of the font is used instead of the embedded version, both texts are rendered.

Happens in both webkit and webkit-ng

I use the following simple one-liner as a minimal test case, it uses PyQt. This assumes the attached files have been placed in the /tmp directory.

python3 -c "from PyQt5.Qt import *; app=QApplication([]); w = QWebView(); w.setUrl(QUrl.fromLocalFile('/tmp/test.html')); w.show(); app.exec_()"