Yes, it's possible that an engineer made a mistake--Boeing will certainly blame everyone else including the pilots and engineers. But the bigger picture here is that the plane might be unstable, it used a "software patch" as a band-aid, and it neglected to inform pilots about the new automated systems.
I suspect the blame lies with Boeing's management and with the FAA for being complicit with Boeing.
I suspect the blame lies with Boeing's management and with the FAA for being complicit with Boeing.