[Bug][PD][NIXL] always send aux on is_last; only expects_state when truthy (#25699)

Co-authored-by: Shangming Cai <csmthu@gmail.com>

python/sglang/srt/disaggregation/nixl/conn.py

@@ -688,8 +688,9 @@ class NixlKVManager(CommonKVManager):
 
                         handles.append(kv_xfer_handle)
 
-                    if kv_chunk.is_last and kv_chunk.state_indices:
+                    if kv_chunk.is_last:
                         dst_info = self.decode_kv_args_table[req.agent_name]
+                        if kv_chunk.state_indices:
                             state_xfer_handles = self.maybe_send_extra(
                                 req.agent_name,
                                 kv_chunk.state_indices,
@@ -702,7 +703,9 @@ class NixlKVManager(CommonKVManager):
                                 dst_state_item_lens=dst_info.dst_state_item_lens,
                                 dst_state_dim_per_tensor=dst_info.dst_state_dim_per_tensor,
                             )
-                        handles.extend(h for h in state_xfer_handles if h is not None)
+                            handles.extend(
+                                h for h in state_xfer_handles if h is not None
+                            )
 
                         if kv_chunk.prefill_aux_index is None:
                             raise RuntimeError("Missing aux index for last chunk")
@@ -1974,8 +1977,11 @@ class NixlKVReceiver(CommonKVReceiver):
                     ]
                 )
 
-        # Mark that we expect state data if state_indices was provided
+        # Mark that we expect state data if state_indices was provided.
-        if state_indices is not None:
+        # Match the prefill-side truthy check: an empty list means the
+        # model has no state types (e.g. dense LLaMA/Qwen), and prefill
+        # won't send state notifs, so we must not expect them.
+        if state_indices:
             self.kv_mgr.transfer_statuses[self.bootstrap_room].expects_state = True
 
         self.started_transfer = True