Problem with multiple inheritance in volt

Hi I have problem with multiple inheritance in volt. The parent block seems to be escaped and output a raw php tag like this example.

{# base.volt #}
{% block bodyhead %}
<div class="header">                    
    <div id="divcity" >Pilih Area Anda &nbsp;
        {{ select('visitor_area', area, 'using': ['id', 'name'], 
        'useEmpty': true, 'emptyText': 'Area...', 'emptyValue': '0') }}
    </div>
</div>
{% endblock %}

{# index.volt #}
{% extends "layouts/base.volt" %}
{% block bodyhead %}
    <p>This is index</p>
    {{ super() }}
{% endblock %}

My expected Output is like this:

<p>This is index</p>
<div class="header">                    
    <div id="divcity" >Pilih Area Anda &nbsp;
        <select name="visitor_area" id="visitor_area">
            <option value="0">Area...</option>
            <option value="1">Bali</option>
        </select>       
    </div>
</div>

But the real Output from phalcon is like this.

<p>This is index</p>    
<div class=\"header\">                  
    <div id=\"divcity\" >Pilih Area Anda &nbsp;
        <?php echo Phalcon\Tag::select(array('visitor_area', $area, 'using' => array('id', 'name'), 'useEmpty' => true, 'emptyText' => 'Area...', 'emptyValue' => '0')); ?>
    </div>
</div>

What is wrong?