Issue #3238360 by lpeabody, briantschu, abramm, seanB:...

 *   category = @Translation("Reference"),

 *   default_widget = "viewsreference_autocomplete",

 *   default_formatter = "viewsreference_formatter",

 *   list_class = "\Drupal\Core\Field\EntityReferenceFieldItemList",

 *   list_class = "\Drupal\viewsreference\Plugin\Field\ViewsReferenceFieldItemList",

 * )

 */

class ViewsReferenceItem extends EntityReferenceItem {

<?php

namespace Drupal\viewsreference\Plugin\Field;

use Drupal\Core\Field\EntityReferenceFieldItemList;

use Drupal\Core\Field\FieldItemListInterface;

use Drupal\Core\TypedData\DataDefinitionInterface;

/**

 * Defines a list item class for views reference fields.

 */

class ViewsReferenceFieldItemList extends EntityReferenceFieldItemList {

  /**

   * {@inheritdoc}

   */

  public function equals(FieldItemListInterface $list_to_compare) {

    $count1 = count($this);

    $count2 = count($list_to_compare);

    if ($count1 === 0 && $count2 === 0) {

      // Both are empty we can safely assume that it did not change.

      return TRUE;

    }

    if ($count1 !== $count2) {

      // One of them is empty but not the other one so the value changed.

      return FALSE;

    }

    $value1 = $this->getValue();

    $value2 = $list_to_compare->getValue();

    if ($value1 === $value2) {

      return TRUE;

    }

    // If the values are not equal ensure a consistent order of field item

    // properties and remove properties which will not be saved.

    $property_definitions = $this->getFieldDefinition()->getFieldStorageDefinition()->getPropertyDefinitions();

    $non_computed_properties = array_filter($property_definitions, function (DataDefinitionInterface $property) {

      return !$property->isComputed();

    });

    $callback = function (&$value) use ($non_computed_properties) {

      if (is_array($value)) {

        $value = array_intersect_key($value, $non_computed_properties);

        // Also filter out properties with a NULL value as they might exist in

        // one field item and not in the other, depending on how the values are

        // set. Do not filter out empty strings or other false-y values as e.g.

        // a NULL or FALSE in a boolean field is not the same.

        $value = array_filter($value, function ($property) {

          return $property !== NULL;

        });

        // Unserialize data property so it can be compared without concern

        // for order.

        if (isset($value['data']) && is_string($value['data'])) {

          $value['data'] = unserialize($value['data']);

        }

        $this->recursiveKsort($value);

      }

    };

    array_walk($value1, $callback);

    array_walk($value2, $callback);

    return $value1 == $value2;

  }

  /**

   * Recursively sort array by key.

   *

   * @param $array

   *   Array to sort recursively.

   *

   * @return bool

   *   Always TRUE.

   */

  protected function recursiveKsort(&$array) {

    foreach ($array as &$value) {

      if (is_array($value)) {

        $this->recursiveKsort($value);

      }

    }

    return ksort($array);

  }

}