Feedjira: Feed update returns duplicates

I am trying to print rss/atom feed updates using ruby. Feedjira seems to be the best bet for this. Unfortunately the update feature does not seem to work properly. I get duplicate entries.

Here is a simple example that produces the problem:

require 'feedjira'require 'pp'feed = Feedjira::Feed.fetch_and_parse "http://lorem-rss.herokuapp.com/feed?unit=second&interval=10"loop do    feed = Feedjira::Feed.update(feed)    pp feed.new_entries    sleep 20end

Any suggestions? Maybe other libraries? Or am I missing something important when using Feedjira?

There a several questions around this topic for Feedzirra the former name for Feedjira, but the update feature seems to be a new feature: http://feedjira.com/updating-feeds.html