I mostly want to leave this here, for anyone doing a web search about this behavior.

During my WebPack build, I repeatedly saw the line:

Declarator name different _elementReadyDirectiveFactory

The message is coming from https://github.com/schmod/babel-plugin-angularjs-annotate/blob/master/ng-annotate-main.js#L785-L788 I don't understand what it indicates and I also wasn't able to resolve this by trial-and-error.