Este é o código do modelo a ser chamado:
<ul {% if level != 0 %} class="collapse" id="collapsable-{{ unique }}-{{ parent_index }}-{{ level }}"{% else %}{% endif %}>
{% for index, val in value %}
{% if val is iterable %}
<li>
<a role="button" aria-expanded="false" aria-controls="collapsable-{{ unique }}-{{ parent_index ~ '-' ~ index }}-{{ level + 1 }}" data-toggle="collapse" href="#collapsable-{{ unique }}-{{ parent_index ~ '-' ~ index }}-{{ level + 1 }}">
[{{ index }}] =>
</a>
{% include _self.templateName with { value: val, level: level + 1, parent_index: parent_index ~ '-' ~ index } %}
</li>
{% else %}
<li>
[{{ index }} =>
{% if val.timestamp is defined %}
{{ val.format('H:i:s d/m/Y') }}
{% else %}
{{ val }}
{% endif %}
]
</li>
{% endif %}
{% endfor %}
</ul>
É assim que o modelo deve ser incluído:
{% include 'AppBundle:Admin:_list_array.html.twig' with { value: result, parent_index: 0, level: 0, unique: random(100000) } %}