A common pattern to check whether a render array is empty and then print the variable is:

{% if content.body | render %}
<div>
{{ content.body }}
</div>
{% endif %}

This might render content.body twice. Instead,

{% set body_rendered = content.body | render %}
{% if  body_rendered %}
<div>
{{ body_rendered }}
</div>
{% endif %}

should be used. The module does this conversion automatically.