One of the recent posts has been showing up as new over and over again on feed readers. I narrowed the problem down to the email address obfuscation in Markdown & Extra. I just upgraded to a more recent version (two new versions had come out since the beginning of December), and one of the changes is that the obfuscation algorithm is now deterministic instead of random. So you should see that article pop up once more as new, if you are reading through the feed, and then never again.