Error: Mismatched anonymous define() module

[monolithed]

My config:

'use strict';

module.exports = function (config) {
    config.set({
        basePath: './',
        port: 9001,

        browsers  : ['PhantomJS'],
        frameworks: ['mocha-debug', 'mocha', 'requirejs', 'chai', 'chai-as-promised' ],
        reporters : ['mocha', 'progress', 'coverage'],

        client: {
            mocha: {
                reporter: 'html',
                ui      : 'bdd'
            }
        },

        preprocessors: {
            'tests/**/*.js': [ 'babel' ],
            '{trunk,utils}/**/*.js': [ 'coverage' ]
        },

        // https://github.com/karma-runner/karma-coverage
        coverageReporter: {
            type: 'html',
            dir : 'cache/coverage/'
        },

        files: [
            'index.js',
            'tests/**/*.js',
        ],

        colors: true,
        autoWatch: false,
        logLevel : config.LOG_INFO,
        singleRun: true
    });
};

package.json

{
    "devDependencies": {
        "grunt"                   : "^0.4.5",
        "grunt-karma"             : "^0.10.1",
        "grunt-babel"             : "^4.0.0",
        "karma-mocha"             : "^0.1.10",
        "karma-coverage"          : "^0.2.7",
        "karma-chai-plugins"      : "^0.4.0",
        "karma-phantomjs-launcher": "^0.1.4",
        "karma-mocha-debug"       : "^0.1.2",
        "karma-requirejs"         : "^0.2.2",
        "karma-mocha-reporter"    : "^1.0.2",
        "karma-babel-preprocessor": "^5.0.0"
    }
}

A test file

define(['../index.js'], function(polyfiller) {

});

➜ grunt test
Running "karma:tests" (karma) task
INFO [karma]: Karma v0.12.31 server started at http://localhost:9001/
INFO [launcher]: Starting browser PhantomJS
INFO [PhantomJS 1.9.8 (Mac OS X)]: Connected on socket laHcJ0unDsVM0KNd31Tc with id 53989432
PhantomJS 1.9.8 (Mac OS X) ERROR
  Error: Mismatched anonymous define() module: function (polyfiller) {}
  http://requirejs.org/docs/errors.html#mismatch
  at /workspace/github/polyfiller/node_modules/requirejs/require.js:141
PhantomJS 1.9.8 (Mac OS X) ERROR
  Error: Mismatched anonymous define() module: function (polyfiller) {}
  http://requirejs.org/docs/errors.html#mismatch
  at /workspace/github/polyfiller/node_modules/requirejs/require.js:141


Finished in 0.027 secs / 0 secs

SUMMARY:
✔ 0 tests completed
Warning: Task "karma:tests" failed. Use --force to continue.

Aborted due to warnings.

Ok,

define('foo', ['../index.js'], function(polyfiller) {

});

➜ grunt test
Running "karma:tests" (karma) task
INFO [karma]: Karma v0.12.31 server started at http://localhost:9001/
INFO [launcher]: Starting browser PhantomJS
INFO [PhantomJS 1.9.8 (Mac OS X)]: Connected on socket w_SmkVVfhA3AXESY5THZ with id 85656734
PhantomJS 1.9.8 (Mac OS X) ERROR: 'There is no timestamp for /workspace/github/polyfiller/node_modules/karma-chai-plugins/node_modules/chai/chai.js!'
PhantomJS 1.9.8 (Mac OS X) ERROR: 'There is no timestamp for /Abashkin/workspace/github/polyfiller/node_modules/karma-chai-plugins/node_modules/chai/chai.js!'

PhantomJS 1.9.8 (Mac OS X) ERROR: 'There is no timestamp for /workspace/github/polyfiller/node_modules/karma-chai-plugins/node_modules/chai-as-promised/lib/chai-as-promised.js!'
PhantomJS 1.9.8 (Mac OS X) ERROR: 'There is no timestamp for /workspace/github/polyfiller/node_modules/karma-chai-plugins/node_modules/chai-as-promised/lib/chai-as-promised.js!'

WARN [PhantomJS 1.9.8 (Mac OS X)]: Disconnected (1 times), because no message in 10000 ms.

Finished in 10.035 secs / 0 secs
Warning: Task "karma:tests" failed. Use --force to continue.
Aborted due to warnings.

What am i doing wrong?