Hello!
On directives I have detected the following problem:

If you include coreDirectives and NgFor in the same component, the ng-for instruction will be executed two times.

Example in this plunker: http://plnkr.co/edit/tFGJVjO3z78GEXCTKFh4?p=preview

I think the framework need report an error with this info or render only one time the ng-for...

Thanks and sorry my bad english 😄