On chrome, 29.0.1547.57 m.
I've used the android app to create comments, as such they appear as below when hovering over them on the desktop version:
Hovering over the x does this:
It's not easy to see in the screenshots, but the comment by Cole Johnson moves down 1 or 2 pixels when I hover over the x.
Comments below shouldn't get jiggled when hovering over the x of a comment submitted via the SE android app.