It is though. Bad products eventually fail under their expected operating conditions. That means you didn't actually make something production ready. It didn't

It is though. Bad products eventually fail under their expected operating conditions. That means you didn't actually make something production ready. It didn't meet the specified requirements. That's a bad product. If I have a car motor which runs, but throws a piston 20k miles before it should, I didn't build to the production spec.