AngularJS scope not updating after data changes in factory method

I feel like I'm missing something obvious here, but I'm still stymied.

I update Thing on the scope by calling the create function on the ThingFactory. But when I reference the scope from PromoteController, the scope still contains the old version of Thing (with ID of 1).

This seems like a place where I'd want to use $scope.$apply(), but that causes the 'digest already in progress' error.

What am I missing?

var app = angular.module('app', ['ngRoute']);

  app.factory('ThingFactory', ['$http', '$q', '$routeParams', function ($http, $q, $routeParams) {

  var deferred = $q.defer();

  return {
      get: function(id) {

          var thing = {
              id: 393,
              name: 'Can I be gotten?',
              description: 'get'
          };
          deferred.resolve(thing);
          return deferred.promise;
      },
      save: function (thing) {
          console.log("ThingFactory -> CREATE");
          var thing = {
              id: 122,
              name: 'after create.',
              description: 'creatine'
          };
          deferred.resolve(thing);

          return deferred.promise;
      },
      init: function() {
          console.log("ThingFactory -> INIT");
          var thing = {
              id: 1,
              name: 'initial value',
              description: 'INIT'
          };
          deferred.resolve(thing);
          return deferred.promise;
      }
  };

}]);

app.config(function ($routeProvider, $locationProvider, $httpProvider) {
  $locationProvider.html5Mode(true);
  $routeProvider
      .when('/build', {
          templateUrl: '/build.html',
          controller: 'BuildController'
      })
      .when('/things/:id/promote', {
           templateUrl: '/promote.html',
           controller: 'PromoteController'
      })
});


app.controller('BuildController', function ($scope, $http, $location, ThingFactory) {
  // HERE I INITIALIZE THE THING
  ThingFactory.init().then(function(thing) {
      $scope.thing = thing;
  });

  $scope.saveNewThing = function() {
      // HERE I 'SAVE' THE THING
      ThingFactory.save($scope.thing).then(function(thing) {
          $scope.thing = thing;
          $location.path("/" + thing.id + "/promote");
      })
  }

});

app.controller('PromoteController', function ($scope, $http, $routeParams, ThingFactory) {
  // HERE'S WHERE THE THING ON THE SCOPE SHOULD HAVE AN ID OF 122,
  // BUT IS STILL 1
  var id = $routeParams.id;
  ThingFactory.get({id: id}).then(function(thing) {
      $scope.thing = thing;
  });
});