diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index da38f34e6a..492005a170 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -140,9 +140,6 @@ class FederationHandler(BaseHandler):
             )
             event = redacted_event
 
-        if state:
-            state = [p for p in state]
-
         is_new_state = yield self.state_handler.annotate_event_with_state(
             event,
             old_state=state
@@ -307,8 +304,6 @@ class FederationHandler(BaseHandler):
                 event
             )
 
-            state = [p for p in state]
-
             logger.debug("do_invite_join state: %s", state)
 
             yield self.state_handler.annotate_event_with_state(