So I just finished 1920. Graham spends a couple minutes on Debs acting like suffragists thanked him by him getting most of their votes (something I'm questionable on to say the least considering Debs' overall level of support). He then talks about the 1920 election representing the end of the Progressive Era of U.S. politics but talks about Wilson before he left office pardoned Debs. I'm like "what!?" I go back and check and Debs was pardoned by Harding, Wilson before he left office explicitly denied it. Pretty egregious error for a show that's usually well-researched.
On the 1968 one I think Graham refers to Rockefeller as a 'New York tycoon' (without referring to his important political position) and says that Nixon won Georgia. He neglects to mention Wallace's candidacy again after going over the major LeMay gaffe, even though Wallace still came quite close to deadlocking the Electoral College.
