Is the issue that the new episode is posted/listed in the
subscriptions view but it's not initiated, or the latest episode
just doesn't show? It's been automatically downloading fine for me
when it becomes available but it's been taking a while for shows to
appear on the list (sometimes couple days etc).
Both issues happened to me. Sometimes the new episodes appear on
the list but doesn't download automatically, other times simply
doesn't appear on the list. Then there's one day that all the
missing episodes start downloading at the same time. I think this
version doesn't work well in Mavericks.