diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index dc69b3cfe7a00b89befdea902856eda1c48ed615..962686f4bb300eea7a35c05c6f1447c9531f16cc 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -370,7 +370,7 @@ class SyncHandler(BaseHandler):
             prev_batch=prev_batch_token,
             state=state_events_delta,
             limited=limited,
-            ephemeral=typing_by_room.get(room_id, None)
+            ephemeral=typing_by_room.get(room_id, [])
         )
 
         logging.debug("Room sync: %r", room_sync)