*********SPOILERS FROM RECENT JUSTICE LEAGUE COMIC***********
In the latest issue of JL it is revealed that Manhunter's past with the JL still involves key stories. Not all but one is certain. The first encounter between the Justice League and Despero.
It also reveals that while with the JL Jonn never really used his powers to there full extent. He always operated under the league's guidelines.
Before it took the entire league to take down Despero. In this issue Jonn takes him down in a couple of pages while not holding back.
Also knowing that Jonn was a part of the team and shares some pre new 52 history with the league, what exactly went down to have the entire league fighting him in a panel from the first couple issues of Justice League?