Angular 2 - Handling multiple subscriptions on a single observable
This is probably due to the fact that your Observable<Response> is a cold observable, i.e. it is 'restarted' for every new subscriber. For an explanation of hot vs. cold observables, have a look at Hot and Cold observables : are there 'hot' and 'cold' operators?. So here you probably subscribe once for the result handler, and another time for the error handler.
You should be able to workaround the subscriptions side effect by 'sharing' your observable,
i.e. replace
var response = super.get(url, options);With
var response = super.get(url, options).share();`