I have OSX Mountain Lion (10.8.4) and Chrome 32.0.1700.107. In my case the behavior is OK.
By default my Chrome does not display scrollbars, they appears only when you're moving with the mouse wheel. Take a look to the screen record I've done (mov file recorded with QuickTime just in case you need a plugin):
http://static.userlinux.net/images/lab/dokuwiki-scrollbar.mov
So, I can't reproduce or didn't really understand the bug.