I’m using version 3150 (but this happens since few revisions), as you can see here,
I’m quite sure I also noticed this in non-italic font, but this is quite noticeable.
FYI, if you’re using pango text for this, I’ve been getting this issue in the past too, and here’s how I got it fixed:
http://bazaar.launchpad.net/~unity-team/unity/trusty/view/head:/unity-shared/StaticCairoText.cpp#L626
