That is if they have communication skills (which most people lack), share the same domain knowledge (usually the guy already knows the problem, and you'll be figuring it out in the next days, so there's no way you can even ask informed questions). Plus recall bias, plus confirmation bias, not to mention pure bullshitting, especially when things go wrong.
Dependence on memory is a system error. It means there's something wrong with the process, or the workplace lacks proper communication.
My default response to "I told you to...", is in every circumstances "no, you didn't". Until they know better.