1 files changed, 2 insertions, 3 deletions
diff --git a/synapse/storage/controllers/persist_events.py b/synapse/storage/controllers/persist_events.py
index f1d2c71c91..35c0680365 100644
--- a/synapse/storage/controllers/persist_events.py
+++ b/synapse/storage/controllers/persist_events.py
@@ -839,9 +839,8 @@ class EventsPersistenceStorageController:
                         "group" % (ev.event_id,)
                     )
                 continue
-
-            if ctx.prev_group:
-                state_group_deltas[(ctx.prev_group, ctx.state_group)] = ctx.delta_ids
+            if ctx.state_group_deltas:
+                state_group_deltas.update(ctx.state_group_deltas)
 
         # We need to map the event_ids to their state groups. First, let's
         # check if the event is one we're persisting, in which case we can