ember-engines: Error when building for fastboot

I created a demo app for migrating to engines in a talk and I found an incompatibility running fastboot on the enginified version (it works without engines).

The error:

⠇ BuildingThe Broccoli Plugin: [AssetManifestGenerator: Asset Manifest Generator] failed with:
Error: Attempting to add bundle "parents-engine" to manifest but a bundle with that name already exists.
    at /Users/miguelcamba/code/engines-demos/smhw-blog/node_modules/ember-asset-loader/lib/asset-manifest-generator.js:83:15
    at Array.reduce (native)
    at AssetManifestGenerator.build (/Users/miguelcamba/code/engines-demos/smhw-blog/node_modules/ember-asset-loader/lib/asset-manifest-generator.js:72:34)
    at /Users/miguelcamba/code/engines-demos/smhw-blog/node_modules/broccoli-caching-writer/index.js:149:21
    at tryCatch (/Users/miguelcamba/code/engines-demos/smhw-blog/node_modules/rsvp/dist/rsvp.js:538:12)

Versions:

• Node 6
• “ember”: “~2.10.0-beta.3”,
• “ember-engines”: “0.4.0-beta.3”
• lazyLoading: Tried with both, same error.

Reproduction:

• Clone https://github.com/mysencare/smhw-ember-engines-demo, branch engines.
• Install ember-cli-fastboot and run ember fastboot --serve-assets