Platform: Error: Effect "<some effect>" dispatched an invalid action: undefined

[cyberbeast]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[*] Bug report  
[ ] Feature request
[ ] Documentation issue or request

What is the current behavior?

When trying to dispatch an action on ngInit, I am getting the following error messages:
Error: Effect "UserEffects.fetchUser$" dispatched an invalid action: undefined and TypeError: Actions must be objects after the dispatched action and the associated effect as executed.

[jibbers42]

To help those landing here from google, you probably returned store.dispatch(action) in your effect instead of simply the action, for example...

bad

@Effect()
  loginSuccess$ = this.actions$.pipe(
    ofType(UserApiActionTypes.LoginSuccess),
    switchMap(_ => this.store$.select(fromAuth.getRedirectUrl)),
    map(url => this.store$.dispatch(new routerActions.Go(url)))
  );

good

@Effect()
  loginSuccess$ = this.actions$.pipe(
    ofType(UserApiActionTypes.LoginSuccess),
    switchMap(_ => this.store$.select(fromAuth.getRedirectUrl)),
    map(url => new routerActions.Go(url)) /* this is the changed line */
  );