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

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>
```