I don't think that would be part of the job of the project management or at most it would be their job to keep the number of change requests as low as possible.

I don't think that would be part of the job of the project management or at most it would be their job to keep the number of change requests as low as possible. In my current project, for example, with have people dedicated to requirements engineering and things are reviewed several times, at least in theory, before they end up in the sprint backlog. But nonetheless I would say that just reading a user story and coding it out is the exception, usually you write a if statement and then notice that there is nothing in the specification that says what to do in case the condition is false. And then you ask and suddenly it turns out that this whole thing totally conflicts what somebody implemented a month ago. Personally I have never worked in a project where people where just supposed to code out a given specification, they were always also involved in gathering requirements and at least to some extend in shaping the architecture. Only the overall system architecture is usually already fixed by architects, most of the time to ensure that the system integrates well with the existing environment.