I'm using open sans (locally hosted as woff) on that site so i'd say it's unlike...

scrollaway on April 12, 2016 | parent | context | favorite | on: Leaving Beta, New Sponsors

I'm using open sans (locally hosted as woff) on that site so i'd say it's unlikely to do with the font itself. Maybe your browser has issues with eot/svg fonts.

Could likely be something to do with fontconfig on your system.