Now that Luke and Ben are retracing Jacen's journey to the foreign Force Cultures, I'm starting to see a pattern. Jacen goes to the Baran Do, and the leader of the Hidden Ones then became unhinged for the next dozen or so years. Jacen goes to the Aing-Tii, and tensions have since broken out between them. Jacen, at some time, had to give Nelani Dinn some lightsaber training, when he was supposed to be travelling around the galaxy. But Luke and Leia and his family don't seem to have known about this, since his return during the Dark Nest crisis was the first time they had seen him in 5 years. Mysterious... If Jacen was somehow "infected" during his journey, and was "infecting" these Force Cultures he visited, maybe the time he came across Nelani was when he infected the Jedi Order... eventually leading to their bizzare ethical code by the time he formally returned to them during the Dark Nest crisis, which they claimed to have gotten from Vergere's teachings. Perhaps those young Jedi who were hidden in the Maw are now showing an extreme version of this infection. Since it has been with them for the last 15 or so years of their lives, starting at a very young age, it has had more time to develop individually in each one of them.