This is something I've noticed for a long time. It never bothered to post about. When I use MN on my iPad, there are duplicate threads, literally, the same thread, listed twice, This only appears to be among the first screen's worth of posts.
Is this because the threads are very active?
I've posted a screenshot where you can see Patriarchy Chicken twice. In this case, the number of posts differs, but it is usually the same.