core/lib/Drupal/Component/Utility/DiffArray.php | 34 +++++++++++++++++++++++++
 core/modules/editor/editor.module               |  3 ++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/core/lib/Drupal/Component/Utility/DiffArray.php b/core/lib/Drupal/Component/Utility/DiffArray.php
index 825648e..e5bc679 100644
--- a/core/lib/Drupal/Component/Utility/DiffArray.php
+++ b/core/lib/Drupal/Component/Utility/DiffArray.php
@@ -47,4 +47,38 @@ public static function diffAssocRecursive(array $array1, array $array2) {
     return $difference;
   }
 
+  /**
+   * Computes the difference of arrays.
+   *
+   * The main difference from the array_diff() is that this method does not
+   * remove duplicates. For example:
+   * @code
+   *   array_diff([1, 1, 1], [1]); // []
+   *   \Drupal\Component\Utility\DiffArray::diffOnce([1, 1, 1], [1]); // [1, 1]
+   * @endcode
+   *
+   * Keys are maintained from the $array1.
+   *
+   * The comparison of items is always performed in the strict (===) mode.
+   *
+   * @param array $array1
+   *   The array to compare from.
+   * @param array $array2
+   *   The array to compare to.
+   *
+   * @return array
+   *   Returns the difference between the two arrays.
+   */
+  public static function diffOnce(array $array1, array $array2) {
+    foreach ($array2 as $item) {
+      // Always use strict mode because otherwise there could be fatal errors on
+      // object conversions.
+      $key = array_search($item, $array1, TRUE);
+      if ($key !== FALSE) {
+        unset($array1[$key]);
+      }
+    }
+    return $array1;
+  }
+
 }
diff --git a/core/modules/editor/editor.module b/core/modules/editor/editor.module
index 7cba938..f181ef1 100644
--- a/core/modules/editor/editor.module
+++ b/core/modules/editor/editor.module
@@ -5,6 +5,7 @@
  * Adds bindings for client-side "text editors" to text formats.
  */
 
+use Drupal\Component\Utility\DiffArray;
 use Drupal\Component\Utility\Html;
 use Drupal\editor\Entity\Editor;
 use Drupal\Core\Entity\FieldableEntityInterface;
@@ -386,7 +387,7 @@ function editor_entity_update(EntityInterface $entity) {
 
     // Detect file usages that should be incremented.
     foreach ($uuids_by_field as $field => $uuids) {
-      $added_files = array_diff($uuids_by_field[$field], $original_uuids_by_field[$field]);
+      $added_files = DiffArray::diffOnce($uuids_by_field[$field], $original_uuids_by_field[$field]);
       _editor_record_file_usage($added_files, $entity);
     }