diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 300cdff82041..212186b1cee3 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -1981,7 +1981,7 @@ async def _get_room_changes_for_incremental_sync(
         for event in membership_change_events:
             mem_change_events_by_room_id.setdefault(event.room_id, []).append(event)
 
-        newly_joined_rooms: List[str] = []
+        newly_joined_rooms: List[str] = list(sync_result_builder.retransmit_room_ids)
         newly_left_rooms: List[str] = []
         room_entries: List[RoomSyncResultBuilder] = []
         invited: List[InvitedSyncResult] = []
@@ -2004,9 +2004,7 @@ async def _get_room_changes_for_incremental_sync(
             # we do send down the room, and with full state, where necessary
 
             old_state_ids = None
-            if room_id in sync_result_builder.joined_room_ids and (
-                non_joins or room_id in sync_result_builder.retransmit_room_ids
-            ):
+            if room_id in sync_result_builder.joined_room_ids and non_joins:
                 # Always include if the user (re)joined the room, especially
                 # important so that device list changes are calculated correctly.
                 # If there are non-join member events, but we are still in the room,