ngMessages validation flicker

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-messages/1.5.5/angular-messages.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.4.8/angular-animate.js"></script>
<div ng-app="myapp">
    <div ng-controller="UserCtrl">
        <form name="user_form" novalidate>
            <input name="name" ng-model="temp.name" ng-show="showField" placeholder="Name" required autocomplete="off"/>
            <ng-messages ng-show="user_form.name.$dirty && !user_form.$valid" for="user_form.name.$error">
              <ng-message when="required">
                Please enter your name
              </ng-message>
            </ng-messages>
            <button type="button" class="button" ng-click="reset()">Reset</button>     
        </form>
        <p>
            Pristine: {{user_form.$pristine}}
        </p>
        
        <pre>Errors: {{user_form.$error | json}}</pre>
              
    </div>
</div>

CSS

ng-messages.ng-hide:not(.ng-hide-animate), [ng-messages].ng-hide:not(.ng-hide-animate)
{
   display: block !important;
   visibility: hidden;
}

ng-messages, [ng-messages]
{
  display: block;
  height: 1em;
}

input
{
  display: block;
}

JavaScript

var $scope;
var app = angular.module('myapp', ['ngMessages', 'ngAnimate']);
app.controller('UserCtrl', ['$scope', UserCtrl]);

function UserCtrl($scope) {
    $scope.showField = true;
    $scope.reset = function() {
        var master = { name: '' };
        $scope.temp = angular.copy(master);
        $scope.user_form.$setPristine();
    }  
}