Webpacker x React x Rails で ERROR in Entry module not found

Question

今回のプロジェクトは初のReact & Railsのプロジェクトで
これまでできていたEC2へのデプロイ時にこのような問題が起きてしまいます。
development環境では全く問題がないのですが、test or production の場合 にmoduleが見つからないという問題が起きてしまいます。

file-loaderは入っているため何が問題かわからないのですが、どこを見るべきかなどでもいいので教えていただければ。
他に必要な情報があれば教えていただければ幸いです。

** [out :: drfellow-test-app1] ERROR in Entry module not found: Error: Can't resolve 'file-loader' in

# Note: You must restart bin/webpack-dev-server for changes to take effect

default: &default
  source_path: app/javascript
  source_entry_path: packs
  public_output_path: packs
  cache_path: tmp/cache/webpacker
  loader: file-loader

  # Additional paths webpack should lookup modules
  # ['app/assets', 'engine/foo/app/assets']
  resolved_paths: []

  # Reload manifest.json on all requests so we reload latest compiled packs
  cache_manifest: false

  extensions:
    - .jsx
    - .js
    - .sass
    - .scss
    - .css
    - .module.sass
    - .module.scss
    - .module.css
    - .png
    - .svg
    - .gif
    - .jpeg
    - .jpg

development:
  <<: *default
  compile: true

  # Reference: https://webpack.js.org/configuration/dev-server/
  dev_server:
    https: false
    host: localhost
    port: 3035
    public: localhost:3035
    hmr: false
    # Inline should be set to true if using HMR
    inline: true
    overlay: true
    compress: true
    disable_host_check: true
    use_local_ip: false
    quiet: false
    headers:
      'Access-Control-Allow-Origin': '*'
    watch_options:
      ignored: /node_modules/


test:
  <<: *default
  compile: true

  # Compile test packs to a separate directory
  public_output_path: packs-test

develop:
  <<: *default

  # Production depends on precompilation of packs prior to booting for performance.
  compile: false

  # Cache manifest.json for performance
  cache_manifest: true

production:
  <<: *default

  # Production depends on precompilation of packs prior to booting for performance.
  compile: false

  # Cache manifest.json for performance
  cache_manifest: true

package.json

{
  "name": "drfellow",
  "private": true,
  "dependencies": {
    "@rails/webpacker": "3.5",
    "ajv": "^6.5.3",
    "babel-preset-react": "^6.24.1",
    "babel-runtime": "^6.26.0",
    "final-form": "^4.10.0",
    "lodash": "^4.17.10",
    "prop-types": "^15.6.2",
    "react": "^16.4.2",
    "react-dom": "^16.4.2",
    "react-final-form": "^3.6.5",
    "react-ga": "^2.5.3",
    "react-redux": "^5.0.7",
    "react-router-dom": "^4.3.1",
    "react-scripts": "1.1.4",
    "react-select": "^2.0.0",
    "react-spinners": "^0.3.3",
    "redux": "^4.0.0",
    "redux-persist": "^5.10.0",
    "redux-thunk": "^2.3.0",
    "webpack": "3.12.0"
  },
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-loader": "^7.1.5",
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-polyfill": "^6.26.0",
    "babel-preset-env": "^1.7.0",
    "file-loader": "^2.0.0",
    "url-loader": "1.0.1",
    "webpack-dev-server": "2.11.2"
  }
}