With the Extra theme there’s a nice little feature called the Timeline which lists posts nicely in month order but the first post is sometimes repeated many times and only a couple of people have had an issue with this it seems, as only two posts appear on the Elegant Themes help forum .
The advise given was to delete the first post that is being duplicated. However one poster remained convinced that it was due to a bug in the theme and I believe this was a true conclusion.
When you create a page and use the timeline template you’ll see the latest post at the top and the first post at the bottom. When you scroll down to the first post you may see that it duplicates indefinitely as you scroll down. The solution is to give the post a more recent date.
The date that causes the problem is the 1st January. It needs to change to the 2nd January. If your first post is not dated 1st January then you will not have a problem. The poster to Elegant Themes was correct, it is a bug.