I believe the part about hard coding production data was referring to recreation of the bug, not implementing the solution which the author describes subsequent

I believe the part about hard coding production data was referring to recreation of the bug, not implementing the solution which the author describes subsequently as "a couple of array functions". There's a fair bit of hand waving going on with technical details throughout but I don't think it's badly intended, more aimed at keeping the focus on the organisational issues described.