The buttons on the left from Quark combined with tinkers' construct's pattern chest makes it possible to dupe blank patterns, if not any pattern.

Video showing bug:
https://www.youtube.com/watch?v=ggH-aTsgB3Y

Have you tried with tinkers construct and quark only?

Closing because I'm cleaning up the issues page. This issue is really old and probably irrelevant. If you feel i should be re-opened please tell me why.