With great powers came great consequences, mania was something that every mecha morph suffered from. But it differed in ranges just as different mecha morphs were divided into various grades those who belonged to the bottom did not suffer much from mania and could live their lives as normal beings but those who belonged to A, S and Z classes suffered gravely from this heavy side effect after awakening their mecha core.
Their tendency to control their emotional outbursts was almost at rock bottom and once they lost control of their reasoning they will end up acting on their instincts. When these high-level mecha morphs lost control there will be no fluctuations in their emotions, in fact even the transmitters won't be able to catch even a single oscillation in their brain waves, they will stay the same as they usually do but once their mania catches up to them they would end up attacking even their loved ones if they made them angry.