diff --git a/syncapi/sync/requestpool.go b/syncapi/sync/requestpool.go
index 1a7ff6e53..8d51689e3 100644
--- a/syncapi/sync/requestpool.go
+++ b/syncapi/sync/requestpool.go
@@ -230,6 +230,7 @@ func (rp *RequestPool) appendAccountData(
 						Content: gomatrixserverlib.RawJSON(databody),
 					},
 				)
+				data.Rooms.Join[r] = j
 			}
 		}
 		return data, nil