I don't even know how to describe this issue. See this example:

http://plnkr.co/edit/41jAiSpDiGTZKfntVB13?p=preview

Because the component <faulty> is both in the component with <ng-content> and the components which is rendered inside of that <ng-content> it throws the error. If you delete <faulty> in either place it works.

This used to work in beta.0