Angular 1.4 BETA Text Binding bug

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.5/angular.min.js"></script>
<body ng-app="myApp">
    <div ng-controller="imageController">
        
        <!-- AJAX loader -->
        <div id="circularG" ng-show='showAjaxLoader'>
            <div id="circularG_1" class="circularG"></div>
            <div id="circularG_2" class="circularG"></div>
            <div id="circularG_3" class="circularG"></div>
            <div id="circularG_4" class="circularG"></div>
            <div id="circularG_5" class="circularG"></div>
            <div id="circularG_6" class="circularG"></div>
            <div id="circularG_7" class="circularG"></div>
            <div id="circularG_8" class="circularG"></div>
        </div>
        
        <!-- Next/Previous buttons -->
        <button id='previous' ng-click='getPrev()' ng-init='showPrev=false' ng-show='showPrev'>Prev</button>
        <button id='next' ng-click='getNext()' ng-show='showNext'>Next</button>
        
        <!-- image -->
        <img src={{url}} orientable />
        
    </div>
</body>

CSS

img{
    width: 100%;
}

button{
    position: fixed;
    top: calc(50% - 17px);
    font-size: 25px;
}

#previous{
    left: 0px;
}

#next{
    right: 0px;
}

/* AJAX loader */

#circularG{
	position:relative;
	width:58px;
	height:58px;
	margin:...

JavaScript

angular
    .module('myApp', [])
    .directive('orientable', function () {       
    return {
        scope: false,
        link: function($scope, element, attrs) {   
           $scope.$watch("url", function(newValue){
            element.bind("load" , function(e){ 

                // success, "onload" catched
                // now we can do specific stuff:

//                $('#circularG').hide();
                $scope.$apply(function(){
                $scope.showAjaxLoader = false;
                });
//                angular.element('#circularG').hide();
            });
           });
        }
    }
	})
    .controller("imageController", ['$scope', function ($scope) {

        var imageArray = [
            'https://s3-us-west-2.amazonaws.com/page-sorter/lymphoma.ca1441745287809.jpeg',
            'https://s3-us-west-2.amazonaws.com/page-sorter/luminosawellness.com1441745729564.jpeg',
            'https://s3-us-west-2.amazonaws.com/page-sorter/louisianalifescience.com1441745729564.jpeg'
        ];

        var index = 0;

        $scope.showAjaxLoader = true;

        $scope.url = imageArray[index];

        if(imageArray.length > 0){
            $scope.showNext = true;
        }

        $scope.getPrev = function(){
            $scope.showAjaxLoader = true;
            index--;
            $scope.url = imageArray[index];
            if(index === 0){
                $scope.showPrev = false;
            }
            $scope.showNext = true;
        };

        $scope.getNext = function(){
            $scope.showAjaxLoader = true;
            index++;
            $scope.url = imageArray[index];
            if(index === imageArray.length-1){
                $scope.showNext = false;
            }
            $scope.showPrev = true;
        };
    }]);