I was testing Rivendel's AI and saw that it creates the same hero in different builds. Basically she does it in any building to be trained regardless of whether or not that's where the hero is made.
Another thing is spam from Revelers units, but they don't cast any skills and aren't active in fights or support. I saw that they are not trained in the Fortress and that a menu was made only for AI in Library, but the unit itself is not even used properly by the AI, as currently they are units that are just stagnant and do not help at all.