Drupal 8 custom type content, getting values for a field of type Taxonomy (hence, Entity Reference), which can have multiple values in the field
I think $node_item->category->referencedEntities() is what you want to use.

You have misspelled the method in your question.

 if ($node_item-&gt;category-&gt;isEmpty() === FALSE) {
    $vars = [];
    // Get referenced entities and add each to array of terms.
    foreach ($node_item-&gt;category-&gt;referencedEntities() as $term) {
      $vars[] = [
        'name' =&gt; $term-&gt;label(),
        'phone' =&gt; $term-&gt;field_phone_number-&gt;value,
        'email' =&gt; $term-&gt;field_email_address-&gt;value,
      ];
    }
  }