EmberJS / Ember-Data: 404's Not Getting Caught

Question

I am trying to catch 404 errors in my ember app, and redirect to /not-found.

I have an errors action on my ApplicationController, and I have an RSVP.on('error') function too but the 404's aren't getting caught. I just get a 404 error thrown to my console from jQuery, but the error is not getting passed to the error handler.

Errors initializer:

import Ember from 'ember';

var initialize = function(container) {
  var errorReporting = container.lookup("service:errorReporting");

  Ember.RSVP.on('error', function(err) {
    Ember.warn("Ember.RSVP error..... Logging error:");
    console.log(err);
    if (err.name && err.name === 'TransitionAborted') {
      Ember.debug("TransitionAborted error. Doesn't look like we should be catching these.");
    } else {
      container.lookup('route:application').send('error', err);
    }
  });

  window.onerror = function(err) { // window general errors.
    Ember.warn("Uncaught error (tripped window.onerror)..... Logging error:");
    console.log(err);
    errorReporting.report(err);
  };

};

export default {
  name: 'errors',
  initialize: initialize
};

The error action on my applicationRoute is huge (and I can post it), but it doesn't even seem to be getting called.

EDIT 1: Route Code

import Ember from 'ember';
import AuthenticatedRouteMixin from 'simple-auth/mixins/authenticated-route-mixin';

export default Ember.Route.extend(AuthenticatedRouteMixin, {

  titleToken: function(model) {
    return model.get('name');
  },

  model: function(params) {
    return this.store.find('location', params.location_id);
  }

});

EDIT 2: ApplicationRoute / Error handler

    error: function(err, transition) {
      if (!Ember.isNone(transition)) {
        transition.abort();
      }

      let errorHolder  = this._getErrorDataFrom(err);
      let errorMessage = this._getErrorMessageFrom(errorHolder);
      let isFourOhFour = (typeof(err.status) !== 'undefined' && err.status === 404) || errorHolder.reason === 'not_found';

      if (isFourOhFour) {
        return this.transitionTo('not-found');
      }

      let requireAuthentication = (errorHolder.reason === 'not_authenticated');
      if (requireAuthentication) {
        window.localStorage.setItem('toast-on-reload', errorHolder.message);
        return this.session.invalidate();
      }

      let isValidationError = ( errorHolder.reason === "validation_error" ||
                                ( !Ember.isNone(errorHolder.errors) && !Ember.isNone(errorHolder.message) ) );
      if (isValidationError) {
        this.toast.error(errorMessage);
        return;
      }

      let verificationRequired = (errorHolder.reason === "verification");
      if (verificationRequired) {
        this.toast.error(errorMessage);
        return this.transitionTo('verification');
      }

      let invalidRequest = (errorHolder.reason === 'unprocessable_entity');
      if (invalidRequest) {
        this.toast.error(errorMessage);
        return;
      }

      this.errorReporting.report(errorHolder);
      this.toast.error(errorMessage);
      return this.transitionTo('error');
    }
  },

  _getErrorDataFrom: function(obj) {
    if (!Ember.isNone(obj.responseJSON)) {
      return obj.responseJSON;
    } else if ( !Ember.isNone(obj.success) || !Ember.isNone(obj.errors))  {
      return obj;
    } else if (!Ember.isNone(obj.jqXHR) && !Ember.isNone(obj.jqXHR.responseJSON)) {
      return obj.jqXHR.responseJSON;
    } else {
      Ember.warn("No error handler available, using default ( {} ). Error:");
      console.log(obj);
      return {};
    }
  },

  _getErrorMessageFrom: function(errorHolder) {
    if ( typeof(errorHolder.errors) === 'object' && !Ember.isNone(errorHolder.errors.message) ) {
      return errorHolder.errors.message;
    } else if (!Ember.isNone(errorHolder.errors)) {
      return errorHolder.errors;
    } else if (!Ember.isNone(errorHolder.message)) {
      return errorHolder.message;
    } else {
      return "Sorry, something went wrong.";
    }
  }