The OP did indeed ask about verbal instructions, but as they pertain to "important product related tasks, or customer requested changes..." I don't think anyone believes that if we tell someone to pick something up and put it somewhere else that a record or some other form of documentation is needed. I'm not exactly sure what "important product related tasks" means in this context, so some form of documentation may or may not be needed. If "customer requested changes" aren't documented somehow though, there could be a problem vis a vis the standard.
One of the several CA's I'm working through provides a good example. Like all real-life scenarios, it was a comedy of errors which led up to a mistake valued probably at 25% of the total project cost.
Customer CAD data descibes an injection molded part via 3d solid geometry, and 3d wireframe curves represinting an insert split line. The split must be followed for cosmetic reasons.
The cad translation fails, and we jump through hoops to extract useable data. During a meeting, or some conversation, the designer is told to follow the curve data for the insert (which takes extra effort to retrieve from the database). Later, the project is shuffled around and another designer is asked to finish up. Right about this time, the customer sends new cad data and its just as corrupt as before. Hoop jumping ensues, and solid data is eventually extracted. The insert split line gets tweaked as a manufacturing impovement, eventually causing rejected parts and an expensive repair.
The split line was not evident in the new cad data recieved by the second designer due to the translation errors, and there was no written evidence/instruction to tip him off that it should be there.
The fix? While the idea to
write down instructions relating to such important customer requirements was floated, it was ultimately rejected. The official fix is to repeat the earlier planning meetings in hopes that all such instructions are remembered and re-stated to any new team members.
I have a low confidence in this solution, and I think we are skirting the real issue.
Part of the problem is that the 'old regime' has (almost literally) BEAT employees into submission to follow verbal orders. Very militaristic. After giving orders, they wash thier hands of the situation. No follow up verification. If someone mis-heard a dimension, too bad, they screwed up. Its a morale killer and cause of a lot of tensions and bad habbits.