diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 242719b7c..d53b716ff 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1079,8 +1079,6 @@ class FederationHandler(BaseHandler):
         handled_events = set()
 
         try:
-            event.internal_metadata.outlier = False
-
             # Try the host we successfully got a response to /make_join/
             # request first.
             try: