Very much this.One thing I've noticed that exacerbates the issue is when there are multiple tweets in a row and the page formatting gets all jerked around after they load. So, instead of taking a user to the place they started, like the newest post, it pushes the view way back up the page and one finds themselves having to scroll down through posts that have already been read in order to locate the next new post. Happens on desktop and mobile, but worse on mobile for obvious reasons.
The more tweets in a row the worse it gets.