Doesn't show up if used within if blocks

[sudheesh001]

{% youtube %} https://youtube.com/watch?v=U6c6qCCPJa4 {% endyoutube %}

shows up correctly but

{% if output.name == "ebook" %}
{% youtube %} https://youtube.com/watch?v=U6c6qCCPJa4 {% endyoutube %}
{% endif %}

fails, while at the same time

{% if output.name == "ebook" %}
<div class="row" style="text-align:center;">
    <iframe width="560" height="315" src="https://www.youtube.com/embed/videoseries?list=PLmcMMZCV897oO5k7pfz23XkzXnCdcKbvn" frameborder="0" allowfullscreen></iframe>
</div>
{% endif %}

Works correctly.