Moving away from bower in 2.15.1 ember-cli version

I'm trying to stop using bower dependencies in my Ember project. I updated ember-cli to 2.15.1 and moved bower dependencies to package.json. Maybe it will be helpfull to know which dependencies:

"font-awesome": "~4.7.0",
"jquery.inputmask": "
"moment": "~2.18.1",
"moment-timezone": "0.5.13"

We also used bootstrap-datepicker as a bower dependency, but due to the error message I swapped it for ember-bootstrap-datetimepicker hoping that it would solve my issue. I reinstalled node_modules, removed bower_components, cleared tmp and dist folders and run npm cache clean && bower cache clean. From the project, I removed bower.json and .bowerrc. I also explicitly defined in package.json bowerDirectory: null so that in ember-cli-build.js broccoli won't be looking for any bower components.

in my ember-cli-build.js :

const isProductionLikeBuild = ['production', 'staging', 'review', 'e2e-testing'].indexOf(env) > -1;
const app = new EmberApp(defaults, {
    fingerprint: {
      enabled: isProductionLikeBuild,
      prepend: envConf.assetsPrefix
    },
    sourcemaps: {
      enabled: !isProductionLikeBuild
    },
    minifyCSS: { enabled: isProductionLikeBuild },
    minifyJS: { enabled: isProductionLikeBuild },
    'ember-cli-babel': {
      includePolyfill: true
    },
    'ember-bootstrap-datetimepicker': {
       "importBootstrapCSS": true,
       "importBootstrapJS": true,
       "importBootstrapTheme": true
     },
    'ember-font-awesome': { fontsOutput: '/assets/fonts' },
    exportConfig: {
      environments: [
        'production',
        'staging',
        'review',
        'e2e-testing'
      ]
    }
  });

When I turn off sourcemaps, app is building correctly. When I don't however, this is what I get after typing ember s:

The Broccoli Plugin: [BroccoliMergeTrees: TreeMerger (vendor & appJS)] failed with:
Error: ENOENT: no such file or directory, open '/Users/martagajowczyk/Desktop/Project/project-frontend/tmp/source_map_concat-input_base_path-http://ift.tt/2jwDhP1'
    at Error (native)
    at Object.fs.openSync (fs.js:641:18)
    at Object.fs.readFileSync (fs.js:509:33)
    at SourceMap.addFile (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/fast-sourcemap-concat/lib/source-map.js:75:31)
    at /Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/broccoli-concat/concat.js:200:16
    at Array.forEach (native)
    at Concat.<anonymous> (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/broccoli-concat/concat.js:198:24)
    at /Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/fast-sourcemap-concat/lib/source-map.js:419:12
    at initializePromise (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/rsvp/dist/rsvp.js:567:5)
    at new Promise (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/rsvp/dist/rsvp.js:1039:33)

The broccoli plugin was instantiated at: 
    at BroccoliMergeTrees.Plugin (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/broccoli-plugin/index.js:7:31)
    at new BroccoliMergeTrees (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:16:10)
    at Function.BroccoliMergeTrees [as _upstreamMergeTrees] (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:10:53)
    at mergeTrees (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/broccoli/merge-trees.js:85:33)
    at EmberApp._mergeTrees (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/broccoli/ember-app.js:1832:12)
    at EmberApp.javascript (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/broccoli/ember-app.js:1307:17)
    at EmberApp.toArray (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/broccoli/ember-app.js:1689:12)
    at EmberApp.toTree (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/broccoli/ember-app.js:1711:38)
    at module.exports (/Users/martagajowczyk/Desktop/Project/project-frontend/ember-cli-build.js:46:14)
    at Builder.setupBroccoliBuilder (/Users/martagajowczyk/Desktop/Project/project-frontend/node_modules/ember-cli/lib/models/builder.js:56:19)

What can be the reason of linking to bower_components? Thanks

Output from ember version --verbose && npm --version && yarn --version:

ember-cli: 2.15.1
http_parser: 2.7.0
node: 6.10.3
v8: 5.1.281.101
uv: 1.9.1
zlib: 1.2.11
ares: 1.10.1-DEV
icu: 58.2
modules: 48
openssl: 1.0.2k
os: darwin x64
3.10.10
0.24.6