Problem displaying items of array while it works for non-nested items

[limitcracker]

trafficstars

While it works fine for meta_box.rating which is a no-nested item I have problem displaying items in an array like below:

<div class="card mb-2">
        <h4 class="card-title d-inline-block" data-content="meta_box.taxonomy_grades[0].name">
        </h4>
</div>