The question is not about what kind of errors you've seen, but how they have been initially described.
One more time: Have you ever seen errors described as (and at the time appear to be) "random", and then turn out not to actually be random when more information is available?
Well I hope your not implying random errors don’t exist - they are commonly found in all areas of study.
But yes as I said before the vast number of computer software errors are caused by humans and not random.