diff --git a/lightllm/server/httpserver_for_pd_master/manager.py b/lightllm/server/httpserver_for_pd_master/manager.py
index 18cfa0d51..a80d2926c 100644
--- a/lightllm/server/httpserver_for_pd_master/manager.py
+++ b/lightllm/server/httpserver_for_pd_master/manager.py
@@ -211,19 +211,22 @@ async def _generate_one(
         block_group_request_id = origin_request_id
         p_node = None
         d_node = None
-        prefill_load_released = False
+        # 只有真正累加过 dispatched_prompt_chars 才需要（且只能）扣减一次。
+        prefill_load_charged = False
 
         try:
             p_node, d_node = await self.select_p_d_node(prompt, origin_sampling_params, multimodal_params)
-            # 记录当前 P 节点的在途 prompt 负载，首 token 生成后即可释放。
-            p_node.dispatched_prompt_chars += len(prompt)
-
-            history_gen_token_strs = []
 
             if not p_node or not d_node:
                 logger.error(f"{origin_request_id}: No p_node or d_node found")
                 raise Exception(f"{origin_request_id}: No p_node or d_node found")
 
+            # 记录当前 P 节点的在途 prompt 负载，首 token 生成后即可释放。
+            p_node.dispatched_prompt_chars += len(prompt)
+            prefill_load_charged = True
+
+            history_gen_token_strs = []
+
             origin_prompt_cache_len = None
 
             for iter_index, block_max_new_tokens in enumerate(max_new_tokens_list):
@@ -255,9 +258,9 @@ async def _generate_one(
                     if iter_index == 0 and origin_prompt_cache_len is None:
                         origin_prompt_cache_len = metadata.get("prompt_cache_len", 0)
                     metadata["prompt_cache_len"] = origin_prompt_cache_len or 0
-                    if not prefill_load_released:
+                    if prefill_load_charged:
                         p_node.dispatched_prompt_chars = max(0, p_node.dispatched_prompt_chars - len(prompt))
-                        prefill_load_released = True
+                        prefill_load_charged = False
                     yield origin_request_id, request_output, metadata, finish_status
 
                 await self.remove_req(group_request_id=block_group_request_id)
@@ -277,8 +280,9 @@ async def _generate_one(
             raise e
 
         finally:
-            if p_node is not None and not prefill_load_released:
+            if prefill_load_charged:
                 p_node.dispatched_prompt_chars = max(0, p_node.dispatched_prompt_chars - len(prompt))
+                prefill_load_charged = False
             await self.remove_req(block_group_request_id)
         return