I created a video on the subject. The bug is very "selective" location-wise and only works if the is pointing north with at least a single piece of redstone in front of it. That piece of redstone is in MOST cases required to be connected to another piece (anywhere as long as it comes in contact with the other piece of redstone). After this, you simply apply a redstone pulse to the repeater, causing it to pulse rapidly, acting like a redstone clock.

This was run in a Vanilla minecraft environment.
World: Superflat (Redstone Ready)
Account: agt72508

Hardware Details:
Windows 7 Professional (genuine) Service Pack 1
8GB of ram (7GB dedicated to Minecraft)
SSD Memory connected to mother board by standard SATA cable
Cheap Sapphiretech graphics card (I can't pinpoint which one specifically)
Intel Core i7 3.40 GHz 64 bit processor

Dropbox link to the world download and video (download but can be viewed online): https://www.dropbox.com/sh/b1dx1jd8fhe48t2/AAAV8We0BMntbbF9Y59X5ym1a

Contact:
gabriel.tofvesson@hotmail.com
@GTofvesson