Stability has never really been the defining factor of Stepper's existence, nor his mind. When his former teammate Ricochet developed the coveted 'Targetmaster' technology, the envious Stepper created his own spark-less, processor-less Targetmaster that he dubbed "Nebulon". Essentially just a remotely controlled puppet, Stepper was a talented-enough ventriloquist to convince everyone that Nebulon was a real, living bot. At times, he even convinced himself.
Stepper, then partnered with the slightly unhinged Drift, was assigned the task of hunting down any intruders from neighboring universal streams. During a confrontation with a team of "Gobots", Nebulon was destroyed. The resulting explosion opened a rift in reality, which sent Stepper spiraling into the Axiom Nexus, where he currently resides.
Irony struck when Stepper met his newest partner, an actual, living Nebulon. This 'new' Nebulon has helped bolster the confidence of Stepper through positive reinforcement and more than a little bit of manipulation. Nebulon is the new puppet master, and his less-than-legal ambitions are becoming reality through his loyal marionette, Stepper.