reader view doesn't show tweets
If an article embeds tweets, they do not show up when in reader view.
That is the way Reader View works. The main content is shown and the rest of the page doesn't appear. The 'author' of the coding used used to provide the "reader view" made the determination of what the Reader View will display. But it may be that data which is refreshed or dynamically added to the webpage just can't be displayed in Reader View.