I have a web app I'm developing using AngularJS, D3, Pixi.js, and gulp as a build system. It all works great together, except `gulp-sass`. Here's the relevant code:

```
gulp.task('sass-dev', ['clean-dev'], function() {
  return gulp.src( cfg.appFiles.rootSass )
    .pipe( sass({ errLogToConsole: true }))
    .pipe( gulp.dest( cfg.buildDir+cfg.destDirs.css  ) )
    .pipe( livereload( server ) );
});

```

`cfg` is just a variable that has predefined globs. If I make the third line 

```
 .pipe( sass({ errLogToConsole: true, sourceComments: 'map' }))

```

by adding the mapping of the source (useful for debugging), I get the following fatal error.

```
Assertion failed: (val->IsString()), function _NanGetExternalParts, file ../node_modules/nan/nan.h, line 1725.
Abort trap: 6

```

On my colleague's computer, it works perfectly with or without mapping. On mine, it fails every time with the source comments mapped, and works perfectly without mapping. Both computers are iMacs running the latest version of `node` (`npm`), `bower`, and `OS X`. 

Any idea what could be causing this? Issue in `gulp` or `gulp-sass` itself?