"https://registry.npmjs.org/e_helpers_io.js - Not found" error when installing via NPM

[Zubaja]

When running npm install react-tracker --save I'm getting a '404 - Not Found' error on a dependency, and the package won't install. Here's the entire log:

npm ERR! code E404
npm ERR! 404 Not Found - GET https://registry.npmjs.org/e_helpers_io.js - Not found
npm ERR! 404 
npm ERR! 404  'e_helpers_io.js@latest' is not in the npm registry.
npm ERR! 404 You should bug the author to publish it (or use the name yourself!)
npm ERR! 404 It was specified as a dependency of 'encore'
npm ERR! 404 
npm ERR! 404 Note that you can also install from a
npm ERR! 404 tarball, folder, http url, or git url.

I'm not sure if this is an error on NPM's side, or if the package should be updated accordingly.