Addon causes linked apps to error during build. "Babel loaded v6.x.x"

[Alonski]

I have been having issues using the latest release, v0.4, inside an addon that is linked to another app. Steps:

1. The addon and app have version ember-cookies: 0.4 set as a dependency.
2. Inside the addon I yarn link
3. Inside the app I yarn link addon
4. I ember s in the app and get this error:

Build Error (broccoli-persistent-filter:Babel > [Babel: ember-cookies]) in ember-cookies/clear-all-cookies.js

Requires Babel "^7.0.0-0", but was loaded with "6.26.3". If you are sure you have a compatible version of @babel/core, it is likely that something in your build process is loading the wrong version. Inspect the stack trace of this error to look for the first entry that doesn't mention "@babel/core" or "babel-core" to see what is calling Babel.

What I think is happening is that another addon/dependency has Babel 6 declared as a dependency. This is causing the build to sometimes load Babel 6 and not Babel 7.

I ended up downgrading. Any ideas what can be done?

[BryanCrotaz]

I'm seeing this in 0.3.1