2 files changed, 6 insertions, 0 deletions
diff --git a/changelog.d/15069.misc b/changelog.d/15069.misc
new file mode 100644
index 0000000000..e7a619ad2b
--- /dev/null
+++ b/changelog.d/15069.misc
@@ -0,0 +1 @@
+Faster joins: omit device list updates originating from partial state rooms in /sync responses without lazy loading of members enabled.
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 3a9cddf15a..4e4595312c 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -1399,6 +1399,11 @@ class SyncHandler:
                 for room_id, is_partial_state in results.items()
                 if is_partial_state
             )
+            membership_change_events = [
+                event
+                for event in membership_change_events
+                if not results.get(event.room_id, False)
+            ]
 
         # Incremental eager syncs should additionally include rooms that
         # - we are joined to