I made a post ten minutes ago, 22:26 central standard time, and it says “yesterday 22:26” o.O everything says “yesterday” or later. Doing this on Chrome and Safari, latest versions of both, under OS X 10.9.
I’ve noticed it under windows, using chrome, but it seems inconsistent, where as OS X it’s happening to me constantly.
My Time is set properly in my account settings, too.