@kimchibap
If you don't want to wait, you can always use an older release of calibre that does not suffer from the specific bug. Try the previous release 2.66:
http://download.calibre-ebook.com/2.html
http://download.calibre-ebook.com/2.66.0/
This is indeed a calibre bug. Other similar reader apps such as
MapleRead and Hyphen Reader discussed on mobileread forum also suffer similar problems with calibre 2.67.