md-select not binding to the object referenced by ng-model - angularjs

Question

I have a form with some md-select dropdowns which im trying to bind with a scope object in my angular controller.
The html looks like that :
<div id="horizontal_form_category" class="row">
<div class="col-md-2 col-lg-2" data-ng-repeat="r in categories[general]" dir="rtl">
<md-input-container>
<label> {{ r.name }} </label>
<md-select ng-model="formObject[r.name]" class="md-no-underline">
<md-option ng-repeat="option in r.values" ng-value="option "> {{ option }} </md-option>
</md-select>
</md-input-container>
</div>
</div>
The controller has a definition of the object $scope.formObject = {}; (Although it should work without it)
But, unfortunately, the $scope.formObject object in my controller stays empty.
Any ideas what could cause such weird behavior ? I have some normal bootstrap components whom ng-model is written the same and are working just fine.
Thanks

Answer 1

Does this help in any way? - CodePen
The true as the last parameter for $watch checks for changes in the object formObject.
Markup
<div ng-controller="AppCtrl" ng-cloak="" ng-app="MyApp">
<md-input-container>
<label> Options </label>
<md-select ng-model="formObject['Options']" class="md-no-underline">
<md-option ng-repeat="option in options" ng-value="option "> {{ option }} </md-option>
</md-select>
</md-input-container>
</div>
JS
angular.module('MyApp',['ngMaterial'])
.controller('AppCtrl', function($scope) {
$scope.options = ["Earth", "Saturn", "Jupiter"];
$scope.$watch("formObject", function () {
console.log($scope.formObject);
}, true)
});

Answer 2

Apparently there wasnt any bug.
My form's md-select were empty and therefore the formObject was empty.
The minute I started puting values, the formObject got filled, one field at a time, containing only the fields that were set.
I added a default value and everything is now showing correctly, just to be sure this was the "bug".
In retrospect, this bevahiour actually saves me some lines of code so I adopted it :)
Gotta thank #camden_kid answer for the $watch tip, helped me figure it out in matter of seconds.