diff --git a/core/modules/taxonomy/src/Entity/Vocabulary.php b/core/modules/taxonomy/src/Entity/Vocabulary.php
index 7f62ab6..87139e0 100644
--- a/core/modules/taxonomy/src/Entity/Vocabulary.php
+++ b/core/modules/taxonomy/src/Entity/Vocabulary.php
@@ -172,7 +172,8 @@ public static function postDelete(EntityStorageInterface $storage, array $entiti
         }
       }
       if ($modified_storage) {
-        if (empty($field_storage->getSetting('allowed_values'))) {
+        $allowed_values = $field_storage->getSetting('allowed_values');
+        if (empty($allowed_values)) {
           $field_storage->delete();
         }
         else {