RB 2.98 does not update podcasts when invoked from the Dash in Ubuntu 12.10, however it does when invoked from the command line. I tried disabling all plug-ins. Furthermore, when I try to download a new item in the podcast feed, despite saying it failed, it successfully plays the item anyway!
Please let me know if I can provide any more information that might be of use in debugging the problem.
Emre.