1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 833ff41377..d6c064b398 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -78,7 +78,9 @@ class BaseHandler(object):
         context = yield state_handler.compute_event_context(builder)
 
         if builder.is_state():
-            builder.prev_state = context.prev_state_events
+            builder.prev_state = yield self.store.add_event_hashes(
+                context.prev_state_events
+            )
 
         yield self.auth.add_auth_events(builder, context)