There's always small hardware quirks to be accounted for, but when we are talking about machine learning, which is not directly programmed, it's less applicable to blame developers.
The issue is that computer system are now used to whitewash mistakes or biases with a veneer of objective impartiality. Even an accounting system's results are taken as fact.
Consider that an AI trained with data from the history of policing and criminal cases might make racist decisions, because the dataset includes a plenty of racist bias, but it's very easy for the people using it to say "welp, the machine said it so it must be true". The responsibility for mistakes is also abstracted away, because the user and even the software provider might say they had nothing to do with it.