diff --git a/libs/entitlement/src/main/java/org/elasticsearch/entitlement/instrumentation/Transformer.java b/libs/entitlement/src/main/java/org/elasticsearch/entitlement/instrumentation/Transformer.java
index 1977f767014d0..6d4d4edaae162 100644
--- a/libs/entitlement/src/main/java/org/elasticsearch/entitlement/instrumentation/Transformer.java
+++ b/libs/entitlement/src/main/java/org/elasticsearch/entitlement/instrumentation/Transformer.java
@@ -46,7 +46,7 @@ public byte[] transform(
             return instrumenter.instrumentClass(className, classfileBuffer, verifyClasses);
         } else {
             // System.out.println("Not transforming " + className);
-            return classfileBuffer;
+            return null;
         }
     }