diff --git a/src/Processors/RelationshipProcessor.php b/src/Processors/RelationshipProcessor.php
index 8a32fab..815979d 100644
--- a/src/Processors/RelationshipProcessor.php
+++ b/src/Processors/RelationshipProcessor.php
@@ -261,7 +261,7 @@ protected function getEffectedEntries($relationship, $entryIds)
 
             $this->effectedTerms = array_merge(
                 $this->effectedTerms,
-                $terms->keyBy('slug')->all()
+                $terms->keyBy(fn($term) => $term->slug())->all()
             );
         }
     }