AngularJS ignores form submit - forms

Question

I'm using AngularJS v1.2.13 to create a page with a form which will download a user's file on click.
I'm using $sce to enable the injection of the file URL which works fine.
However, the loading of the resource disables the form submit. I'm sure it has to do with the resource load because when I remove the load and hardcode the url it works fine. I've also created a JSFiddle without it and have not been able to reproduce the problem there.
Any ideas on why this is happening and how it can be fixed?
HTML:
<div ng-controller="viewProfileController" data-ng-init="findOne();">
<form method="get" action="{{downloadFileURL}}">
<button type="submit" class="no-button comment-small" >
Download File
</button>
</form>
</div>
Controller:
'use strict';
angular.module('bop.viewProfile').controller('viewProfileController', [
'$scope', 'Users', '$sce', '$routeParams',
function($scope, Users, $sce, $routeParams) {
$scope.downloadFileURL = '';
// Find current user
$scope.findOne = function() {
Users.get({
userId: $routeParams.userId
}, function(user) {
$scope.user = user;
$scope.downloadFileURL = $sce.trustAsResourceUrl($scope.user.file.url);
});
};
}]);
Users Service:
var userServices = angular.module('bop.users', ['ngResource']);
userServices.factory('Users', ['$resource', function($resource) {
return $resource(
'users/:userId',
{ userId: '#_id' },
{ update: { method: 'PUT' } }
);
}]);