Problems with Pubsub Search Feeds in Bloglines?

I've been fiddling with Pubsub searches and created a few search feeds there. When I add a search feed to Bloglines it shows the entry but the feed hardly ever updates. The one I've still got in there has updated twice in two weeks even though it's updating much more frequently when I check at the pubsub site. I found a blog post citing a similar problem. Anybody have any idea what the problem is? Anybody doing this same thing without any problems?