Civil War!
In these turbulent times when the Genre Representatives broke free of the control of the Systems, in a time of war where Grade 3 and Grade 4 Systems were busy facing the representatives, and in a situation where the fate of the Grade 2 Systems was unknown, the Grade 1 Systems formed the bulk of the army power possessed by the System World.
But when a portion of them retaliated against the remainder, things became chaotic.
A System could only devour and assimilate the powers of Systems from the same genre as itself. If it devoured any foreign Core Skill, it would be wounded based on the level difference between the two. It might even implode if it devoured a higher levelled Core Skill.
That situation only applied when they remained a System though. The Grade 1 Systems that had become members of Secret Society had been awaiting the perfect opportunity to sneak attack.