diff --git a/modules/thunder_gqls/src/Plugin/GraphQL/DataProducer/ThunderSearchApiProducerBase.php b/modules/thunder_gqls/src/Plugin/GraphQL/DataProducer/ThunderSearchApiProducerBase.php
index 13aeb8a17..1bfa6d0a6 100644
--- a/modules/thunder_gqls/src/Plugin/GraphQL/DataProducer/ThunderSearchApiProducerBase.php
+++ b/modules/thunder_gqls/src/Plugin/GraphQL/DataProducer/ThunderSearchApiProducerBase.php
@@ -40,7 +40,7 @@ abstract class ThunderSearchApiProducerBase extends DataProducerPluginBase imple
    *
    * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
    */
-  protected ClassResolverInterface $classResolver;
+  private ClassResolverInterface $classResolver;
 
   /**
    * {@inheritdoc}