I can now confirm that removing the woff files of the font: with rm -rf /usr/share/fonts/woff/fantasque-sans fixes the issue. With woff removed, the otf version of the font is picked and rendered correctly.
- Bug#956950: fonts-fantasque-sans: fantasque-sans font... Konstantinos Poulios
- Bug#956950: Acknowledgement (fonts-fantasque-san... Konstantinos Poulios