Patching Crystal font leads to strange effect on UTF-8 characters

Environment: Ubuntu 14.04, $LANG=ja_JP.UTF-8

Patching https://github.com/whistler/monospace-fonts/blob/master/crystal.ttf is successful, but causes Japanese glyphs to be rendered oblique where they appear.

Did not observe this error on any other fonts I have tried.

Steps to reproduce:

export LANG=ja_JP.UTF-8
./powerline-fontpatcher crystal.ttf
mv "Crystal for Powerline.ttf" ~/.fonts/
fc-cache -v ~/.fonts/

Set terminal font accordingly, type, say, apt-get.

Interestingly enough, the right arrow glyph at the end of the powerline prompt is also oblique in this font after patching.