That’s likely because you are asking the api for a paginated list of posts/comments. When you request page 1 at one point and page 2 at a later time, the list of posts can change inbetween, so posts that were part of page 1 have now been pushed down into page to, so you get them again when loading page 2. The solution is to keep a list of post ids that are already in your list of posts and don’t load those again, same with comments.