After the first clicking on the sorting link in the table header, nothing happens. User has to click twice to make the column sorted. It can be reproduced in Showcase - http://localhost:8080/showcase/richfaces/component-sample.jsf?demo=dataTable&skin=blueSky.
This bug doesn't occur in the last downloadable snapshat (richfaces-showcase-4.1.0-20111111.110230-135-jbas7.war), but it can be found when you build showcase from GitHub repo manually.
It works correctly in Metamer.