A more experienced novelist gave me a hard time once for talking too much about the story I was working on. To be fair, I'd dumped ten minutes of exposition on him -- too much by anyone's standards. "You should never talk about your work-in-progress," he said. "Put that energy into writing, not talking."
Some writers leak details of their ongoing work for publicity reasons. That's a different matter. The concern this writer had was that, by talking, I was satisfying my urge to tell the story. The chatter served as a release valve, bleeding off the pressure until I could safely return to procrastiation.
Since then I've published five books and spent a lot of time with aspiring writers. I see them doing the same thing I used to do, and I give the same advice. Don't talk about what you're working on; work on it. Then you won't have to talk about the story because the story will do its own telling.