The head bearing is not in the electrical circuit, not part of the path. The head bearing is further mechanically isolated from the motor / chain / belt / inverter etc. the path to ground is much lower resistance through the frame than the head bearing, bonding strap or not.
In order for there to be pitting from electrostatic discharge, that is sufficient enough to evaporate steel at 1500 degrees C, there would need to be arcing from the inner race to the outer race/ race to balls/ Something... there is nothing in the front end, on the wheel in the wheel or axle to generate static electric to cause it to want to jump from the inner race to the outer race, and again, the frame is a far less resistive path for current discharge than trying to sneak to a mechanically isolated object and THEN back to ground. static electric is going to ground itself on the frame / forks before trying to jump to the inner race to goto ground.
This isn't a motor bearing, generator or rotor bearing. There also is nothing making / flowing juice inside to want to jump outside.
Damage is most likely due to wear, poor lubrication, excessive abuse, contamination, or shock from a crash or really nasty pothole perhaps, and then it exasperated.
Arcing damage is also very tell tale, you won't mistake it when you see it. If you had that much build up - up front to cause it,it'd also more than likely be raising total hell with the electronic controls on the handlebars, the display unit too.
When you get this bearing out IF you decide change it, can you please take pictures of the damage and post it, that way we can possibly see what caused it, or more than likely what did NOT cause it.
Thank you.
Aaron