Ordering by date not working [bug]

{% set options = { items: '@root.descendants', 'order': {'by': 'date', 'dir': 'asc'}, 'pagination': false } %}
{% set main_collection = page.collection(options) %}

{% for p in main_collection %}
    {% set image = p.media[p.header.image].cropZoom(540, 310) %}

    <article class="main-news">
        <a href="{{ p.url }}" class="d-block mb-3">
            <img src="{{ image.url }}" alt="{{ p.title }}" class="img-responsive w-100 rounded">
        </a>

        <a href="{{ p.url }}">
            <h4>{{ p.title }}</h4>
        </a>
    </article>
{% endfor %}