Wouldn't this situation be part of the agenda for Management Review? I seem to remember that there's a requirement to consider changes affecting the management system...I'd have thought that the review - if done by someone who knows the ISO requirements (like the MR) would have avoided the need for auditors to 'catch' the change later...(maybe too late!)
Too late. Yes, late, but that is going to happen. Perfect planning is what we are striving for. We even achieve it sometimes, but certainly not always. Someone needs to be checking it, though. Management review isn't going to review the nitty-gritty, day-to-day changes that are made. Management review isn't going to review work instruction changes, especially in larger companies.
That type of review isn't going to happen even in smaller companies. Let's take machining process changes for instance. Management review wouldn't review those. Management review may review the training needs for those that are authorized to make those changes based on some sort of KPI perhaps. "Wow, look at all this re-work we've had since the new machine was purchased. Let's get to the bottom of this. Why hasn't the manager in that cell solved this yet?" Then elevation occurs.
The internal quality audit won't necessarily go deep into this type of investigation either, unless they are auditing a failing corrective action. However, they ought to be reviewing changes made to work instructions and the like. This is where there is added benefit. IQA should be looking at what changes are made and conformance to the standard. Although it isn't a delineated requirement, IQA should also be taking a look at customer specific requirements as well. All customer-specific requirements aren't likely to be found in the company's quality manual either. (Now I'm really getting off topic.)
Sometimes the, "What if this happened?" type questions and arguments go too far. But if these types of questions are what could be normally expected, then I think they are reasonable. These types of things can be planned for and double checked, or "Monitored and Measured". Those that wrote the standard have already thought of this too.