Well... I believe that both are true. Fujitsu and the Post Office colluded to hide the errors. And all of the sentences against postmasters were based solely on the fact that the software was infallible. If these defects had not been denied, the consequences would have been very different. That's why I say there is no doubt. Yet, you are right that the cause of this was corruption, and I add the justice system, which took 20 years to start delivering true justice.

BTW the weight of assuming that software cannot be wrong was so hard, that the British Computer Society said that "Computer always right' law must be revisited"