AJAX only works when I’m logged as Admin

I want to make an AJAX request on every select value change to update the real value from database. I’m coding inside a shortcode on functions.php. I have a select element like this one below,

echo '<select name="changeValue" onchange="changeValue(' . $user->ID . ', this.options[this.selectedIndex])">'

At the end of the shortcode, I do:

?>
    <script type="text/javascript">
        function changeValue(id, valueElement) {
            jQuery.post(
                "<?php echo admin_url('admin-ajax.php'); ?>", 
                {
                    'action': 'update_value',
                    'data':  {
                        user_id: id,
                        value: valueElement.value
                    }
                }, 
                function(response){
                    console.log(response)
                }
            );
        }
    </script>
<?
}
add_shortcode('the_shortcode', 'the_shortcode');

function update_value() {
    $user_id = $_POST['data']['user_id'];
    $value= $_POST['data']['value'];
    echo $user_id . ' - ' . $empresa;

    //return update_user_meta($user_id , 'value', $value);
    wp_die();
}
add_action( 'wp_ajax_update_value', 'update_value' );
add_action( 'wp_ajax_nopriv_update_value', 'update_value' );

My code works when I’m logged as Admin. However if I’m logged as another user, console.log(response) returns the whole HTML page content. What am I doing wrong?

EDIT: Another difference is that when logged as Admin, admin-ajax.php returns 200 OK, whereas when logged as a user it returns 302 Found.

What a type you work with response
If you work with json

$.post( ajaxurl , data , function(res){
// your code 
},'json');

Remove wp_die() and replace with die()