diff --git a/python/sglang/srt/two_batch_overlap.py b/python/sglang/srt/two_batch_overlap.py
index 6d2d73028..fc419b03c 100644
--- a/python/sglang/srt/two_batch_overlap.py
+++ b/python/sglang/srt/two_batch_overlap.py
@@ -490,6 +490,7 @@ class TboForwardBatchPreparer:
         output_dict["spec_info"] = output_spec_info
         for key in [
             "forward_mode",
+            "is_extend_in_batch",
             "return_logprob",
             "req_to_token_pool",
             "token_to_kv_pool",