So, I checked the feed and it does have both <guid>
and <pubDate>
elements... which makes me think that Twitterfeed is not able to get the content from the pipe's RSS feed.
I know from practice that Yahoo Pipes is quite aggressive and tends to block services who poll them too often. It's quite likely that Twitterfeed has a lot of Yahoo Pipes feeds and they may be blocked, but only someone from Twitterfeed and/or Yahoo Pipes will be able to confirm that.