The error was due to a node module that was not fully upgraded. I searched the entire node modules directory using the search function on atom for “PropTypes } from ‘react'” and react-router-dom came up. I upgraded the package to the most recent one and the warning was gone.
Well the warning seems like you are importing prototypes directly from react rather than using prop-types. If you change to use the prototypes from prop-types package/module, it should fix the issue.
