I have a lot of problems with this man in general but this is one of my biggest. This was the 2010 episode with Bryan Williams as the main guest (lol). This was part of the segment about Laura Schlesinger using the word on her radio show, and was followed by a bit where he, John Oliver and Wyatt Cenac argue about what the worst word is.
Jon says some pretty crazy stuff (including implying that black people don't have a reason to be as offended by the n-word as Sarah Palin is the r-word) but at one point he just straight up lies and says he said both during the segment, when in reality he flat out refused to say the r-word at all but happily said this.
This was also around the time the famous fight between him and Wyatt Cenac happened. I'm still not sure how on board with this bit Wyatt was (it really seems like Jon snuck the n-word in behind his back) but in addition to the fight Wyatt said Jon basically terrorized him in to quitting after it happened. IDK it just really rubs me the wrong way, especially combined with all my other problems with him.