No risk at all. Her target audience for this “leak” are independents, libertarians and the center right types who voted for Bush, McCain and Romney...the kind who actually read these sites.. not 18-34 yr olds.
She is losing or tied with trump because she is not able to attract millennial voters. And she’s going to leak a story about her calling them bernies basement baristas? I don’t think so. It may make some soft republicans and indies comfortable. But it’s a huge net loss in terms of turnout.