diff --git a/python/sglang/srt/managers/tokenizer_manager.py b/python/sglang/srt/managers/tokenizer_manager.py
index 0d63f608a..64a69018d 100644
--- a/python/sglang/srt/managers/tokenizer_manager.py
+++ b/python/sglang/srt/managers/tokenizer_manager.py
@@ -1444,6 +1444,12 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
             for i in range(batch_size):
                 tmp_obj = copy.copy(objs[i])
                 tokenized_obj = copy.copy(tokenized_objs[i])
+                # Ensure independent mm_items so wrap_shm_features won't mutate the original
+                if hasattr(tokenized_obj, "mm_inputs") and tokenized_obj.mm_inputs:
+                    tokenized_obj.mm_inputs = copy.copy(tokenized_obj.mm_inputs)
+                    tokenized_obj.mm_inputs.mm_items = [
+                        copy.copy(item) for item in tokenized_obj.mm_inputs.mm_items
+                    ]
                 tokenized_obj.rid = tmp_obj.regenerate_rid()
                 tokenized_obj.sampling_params = copy.copy(tokenized_obj.sampling_params)
                 tokenized_obj.sampling_params.max_new_tokens = 0
@@ -1457,6 +1463,12 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
                 for _ in range(obj.parallel_sample_num):
                     tmp_obj = copy.copy(objs[i])
                     tokenized_obj = copy.copy(tokenized_objs[i])
+                    # Ensure independent mm_items so wrap_shm_features won't mutate the original
+                    if hasattr(tokenized_obj, "mm_inputs") and tokenized_obj.mm_inputs:
+                        tokenized_obj.mm_inputs = copy.copy(tokenized_obj.mm_inputs)
+                        tokenized_obj.mm_inputs.mm_items = [
+                            copy.copy(item) for item in tokenized_obj.mm_inputs.mm_items
+                        ]
                     tokenized_obj.rid = tmp_obj.regenerate_rid()
                     self._init_req_state(tmp_obj)
                     tokenized_obj.time_stats = self.rid_to_state[tmp_obj.rid].time_stats