Whenever you cast a downvote, if you have less than 2k reputation, you get a message reminding you
Please consider adding a comment if you think this post can be improved.
This used to be shown near the downvote button, but a few days ago it changed into a banner at the top of the screen.
Now when reviewing First Posts, after clicking 'I'm done', a new review item is dynamically loaded into the page. However, this banner is not dismissed (see below). I consider this a bug since I'm sure the old message was automatically dismissed, and old-style 'Thanks, we'll take a look at it' popups after flagging a post are still dismissed automatically.