diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index b61831d604e8..67fd34dd08a9 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -424,7 +424,6 @@ def make_base_prepend_rules(
                 "kind": "related_event_match",
                 "key": "sender",
                 "pattern_type": "user_id",
-                "_id": "_sender",
             },
         ],
         "actions": ["notify", {"set_tweak": "highlight", "value": False}],