Broken UI Text with dynamic font.

Hi.
I'm using UI Text with dynamic fonts.
I found it work well, but sometimes letters are broken, more often when I use Japanese font.
(I attached an image for reference)
Seems it has some relations with font texture updated dynamically by Unity Engine.

I currently use unity 4.6.1f1(for Win) and 4.7.0(for Mac), and it happens on both versions.

Is there any solution for this?
If it’s unavoidable, can you tell me any tricks or… tips for a shift?
Any help would be much appreciated. :)