Oh, that was a tricky bug! Thank you for report. FIY: Nginx was sending content-type headers two times, first was application/octet-stream and then text/html. C

Oh, that was a tricky bug! Thank you for report. FIY: Nginx was sending content-type headers two times, first was application/octet-stream and then text/html. Chrome/Safari was using last one, Firefox - first one.