Error: only one instance of babel-polyfill is allowed

[navcsdev]

When I run npm install and then run npm start with node version v6.2.0. I get error: Error: only one instance of babel-polyfill is allowed at Object.<anonymous> (/Volumes/DATA/research/serverless-graphql-relay/node_modules/babel-polyfill/lib/index.js:10:9) at Module._compile (module.js:541:32) at Module._extensions..js (module.js:550:10) at Object.require.extensions.(anonymous function) [as .js] (/Volumes/DATA/research/serverless-graphql-relay/node_modules/babel-register/lib/node.js:152:7) at Module.load (module.js:458:32) at tryModuleLoad (module.js:417:12) at Function.Module._load (module.js:409:3) at Module.require (module.js:468:17) at require (internal/module.js:20:19) at Object.<anonymous> (/Volumes/DATA/research/serverless-graphql-relay/graphql/schema.js:1:1)