diff --git a/core/modules/comment/lib/Drupal/comment/CommentFieldNameValue.php b/core/modules/comment/lib/Drupal/comment/CommentFieldNameValue.php
index 7907ba8..44f543e 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentFieldNameValue.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentFieldNameValue.php
@@ -26,9 +26,7 @@ public function getValue() {
       }
       $field = $this->parent->getParent();
       $entity = $field->getParent();
-      // Field id is of the form {entity_type}__{field_name}. We set the
-      // optional limit param to explode() in case the user adds a field with __
-      // in the name.
+      // Field id is of the form {entity_type}.{field_name}.
       $parts = explode('.', $entity->getFieldId(), 2);
       if ($parts && count($parts) == 2) {
         $this->value = end($parts);
diff --git a/core/modules/comment/lib/Drupal/comment/Entity/Comment.php b/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
index 6265b1f..c8070a2 100644
--- a/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
+++ b/core/modules/comment/lib/Drupal/comment/Entity/Comment.php
@@ -77,7 +77,7 @@ public function __construct(array $values, $entity_type, $bundle = FALSE, $trans
       // Initialize missed values.
       if (isset($values['field_id'])) {
         $bundle = $values['entity_type'] . '__' . $values['field_name'];
-        $values['field_id'] = $bundle;
+        $values['field_id'] = $values['entity_type'] . '.' . $values['field_name'];
       }
       else {
         $bundle = str_replace('.', '__', $values['field_id']);