1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 0eab1aefd6..5833fee25f 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -163,7 +163,7 @@ class EventContext:
         return {
             "prev_state_id": prev_state_id,
             "event_type": event.type,
-            "event_state_key": event.state_key if event.is_state() else None,
+            "event_state_key": event.get_state_key(),
             "state_group": self._state_group,
             "state_group_before_event": self.state_group_before_event,
             "rejected": self.rejected,