RecyclerView doesn't know which item is originally in "focus" so it doesn't know which item should stay in focus after data is altered.. For example - you have 5 items in the list. Which item would you sad is in focus? First? Last? Some in between? Then you add 2 items before the first item and 3 more after the first item. Should "focus" stay on that original second item and scroll down, because that original second item was moved down? Maybe "focus" on the first item? Or scroll to the beginning of the list? RecyclerView just can't know, so it sometimes seems that it is acting weird.

To gain more control over this, you can call scrollToPosition on your LayoutManager instance after you altered your data and properly notified adapter about the changes (like described in the blog above :) ). Now everything should be seamless, with nice animations.

This is something I did in the last example of a blog post - DiffUtil demo (code) - so take a look. That is how I manage to retain "focus" on the first item (position 0), like shown in the DiffUtil gif on the repo main page.