1 files changed, 3 insertions, 0 deletions
diff --git a/ractor.c b/ractor.c
index a9df241858..317b24dca2 100644
--- a/ractor.c
+++ b/ractor.c
@@ -1188,6 +1188,7 @@ obj_traverse_i(VALUE obj, struct obj_traverse_data *data)
         // already traversed
         return 0;
     }
+    RB_OBJ_WRITTEN(data->rec_hash, Qundef, obj);
 
     struct obj_traverse_callback_data d = {
         .stop = false,
@@ -1644,6 +1645,8 @@ obj_traverse_replace_i(VALUE obj, struct obj_traverse_replace_data *data)
     }
     else {
         st_insert(obj_traverse_replace_rec(data), (st_data_t)obj, replacement);
+        RB_OBJ_WRITTEN(data->rec_hash, Qundef, obj);
+        RB_OBJ_WRITTEN(data->rec_hash, Qundef, replacement);
     }
 
     if (!data->move) {