After upgrading the faunadb driver from 2.13.0 to 2.14.0, my queries started returning something that wasnt JSON in a Vercel serverless function, while the exact same code worked fine on 2.13.0. Another user on Vercel confirmed the same behavior. The reporter said downgrading to 2.13.1 worked, and a maintainer confirmed a fix. Closed May 2020.