1 files changed, 2 insertions, 1 deletions
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 9059382246..b45b179fed 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -291,8 +291,9 @@ class SyncHandler:
         user_id = sync_config.user.to_string()
         await self.auth.check_auth_blocking(requester=requester)
 
-        res = await self.response_cache.wrap(
+        res = await self.response_cache.wrap_conditional(
             sync_config.request_key,
+            lambda result: since_token != result.next_batch,
             self._wait_for_sync_for_user,
             sync_config,
             since_token,