diff --git a/core/modules/content_translation/src/FieldTranslationSynchronizer.php b/core/modules/content_translation/src/FieldTranslationSynchronizer.php
index 13b805df8a..4f97a2bfa1 100644
--- a/core/modules/content_translation/src/FieldTranslationSynchronizer.php
+++ b/core/modules/content_translation/src/FieldTranslationSynchronizer.php
@@ -75,7 +75,7 @@ public function synchronizeFields(ContentEntityInterface $entity, $sync_langcode
         if (!empty($groups)) {
           $columns = [];
           foreach ($groups as $group) {
-            $info = $column_groups[$group];
+            $info = isset($column_groups[$group]) ? $column_groups[$group] : [];
             // A missing 'columns' key indicates we have a single-column group.
             $columns = array_merge($columns, isset($info['columns']) ? $info['columns'] : [$group]);
           }
@@ -93,7 +93,9 @@ public function synchronizeFields(ContentEntityInterface $entity, $sync_langcode
             $this->synchronizeItems($values, $unchanged_items, $sync_langcode, array_keys($translations), $columns);
 
             foreach ($translations as $langcode => $language) {
-              $entity->getTranslation($langcode)->get($field_name)->setValue($values[$langcode]);
+              if (isset($values[$langcode])) {
+                $entity->getTranslation($langcode)->get($field_name)->setValue($values[$langcode]);
+              }
             }
           }
         }