The term 'stochastic' refers to characteristics or properties that are measured and/or understood on a statistical basis rather than on an individual basis, because they are driven or biased by random processes. What's your understanding of the term, if you're not working from a widely-accepted definition?
Two people interpreting a specification in different ways isn't stochastic because human processing is not a statistical process in any meaningful way. Or, to put it another way: given a specification, you could not reasonably enumerate all the ways two humans might interpret it, much less assign statistical likelihood to those outputs.