Now that I'm thinking about..... what Lemon did technically was impeding on the investigation as he fed information to Jussie that potentially gave him time to change up his story and hide evidence. It's arguably just as bad as what Cuomo did considering that they both basically were interfering with criminal investigations even with it being via different methods.
I don't think that it was intentional on his part like the Cuomo situation, but it's still not a good look as you blurred the lines between journalism and personal relationships.