Most likely due to Rampant AI running. Could be wrong, but that is probably making them not fight properly.
When you add the mod, the biters in the currently explored map are turned into the various factions and they should begin to fight.
The fighting will finish soon after, and then it's down to if they encounter eachoher when expanding or when sending out attack waves.
If you were expecting attack waves sent between each biter base, this mod doesn't do that ( yet)
