This paraphrase is a bit short for how much information was given in this whole article.  By only saying “Clinton leads Sander by 2.4 votes, not 2.5 million.” you are leaving out why that fact matters and that is a bulk of this article.  To maybe improve this paraphrase you could say that Clinton is being criticized for claiming she has more votes than she really does.  To properly in text cite this you would have to put quotations around the statement then followed by (Kessler).

Caucuses were held in some states that included some that do not count towards the RCP tally and some by Democrats Abroad, during the time Clinton had claimed here 2.5 million vote lead over Sanders and the result were some small victories in Clintons favor but Sanders received more overall votes making it only a 2.4 million vote lead (Kessler).