I dunno. Some RSS readers, such as the one I use, have been displaying my posts twice. Sometimes at the same time, sometimes the second time is a day later. This happens on a few other blogs I read. FYI, I have no control over this, since the site is managed by WordPress and their software. Unless someone who reads this is intimately familiar with how I could tweak this to change, it’s going to remain.
That’s not to say that sometimes I don’t update posts. Occasionally I fix something, though more often on older posts – even months later – I’ll add an “Edited to Add” at the bottom that’s an update to the story, rather than doing a full new post on the subject. I did this a lot for August 2013’s, “Military Punishing People for Objecting to The Gay?”
So, set your reader to point out edits made to a story, quickly scan it to see if there have been any changes, and then please pardon the WP errors that lead to duplicated, non-edited posts.