Could this be the same issue that is causing the oldest article function not to skip old articles in basic recipes? The issue started with Calibre 0.9.23.
For example, I have a basic recipe to pull RSS feeds for betanews.com. The fields in this basic recipe are as follows (to recreate this issue you will need to create a basic recipe and enter these fields).
class BasicUserRecipe1363558652(AutomaticNewsRecipe):
title = u'Beta News'
oldest_article = 1
max_articles_per_feed = 100
auto_cleanup = True
feeds = [(u'Top Stories', u'http://feeds.betanews.com/bn')]
Using Calibre 0.9.21 this basic recipe correctly returns only articles posted in the last 1 day. Using Calibre 0.9.23, this recipe returns all articles on "http://feeds.betanews.com/bn" page. The oldest is currently 4 days old.
The same issue is happening with my other basic recipes. All were running correctly until I installed 0.9.23.