There's a current discussion on meta StackExchange about extending a change being trialled on the Android Enthusiasts site to other StackExchange sites. This would bring changes to the voting buttons, including animation, and would include the UX site if rolled out everywhere.
The right place for that discussion is obviously the meta level, where it's now happening.
However, with regard to the voting button appearance, I want to ask a question here from a UX perspective. As a very basic principle, the visual appearance of a UI element should be such as to convey what will happen if the user clicks the element. It follows that any ambiguity or contradiction in the message(s) conveyed is undesirable. Is it just me, or does the proposed voting button appearance have this very problem?
EDIT: I've discovered it's browser-specific: the dots don't show up in IE or FireFox, but they do in Opera. So I'm now thinking it may be a bug rather than a design. May depend on browser versions etc but anyway I think the question of whether what the screenshot shows would be a good design, and if not why not, remains interesting.