[Generative Score API] Fix on prefill-only scheduler running batch loss track problem

python/sglang/srt/managers/scheduler.py

@@ -2074,14 +2074,21 @@ def get_next_batch_to_run(self) -> Optional[ScheduleBatch]:
                 self.running_batch.batch_is_full = False
 
             # Merge the new batch into the running batch.
-            # For prefill-only batch, we can avoid going through decoding step.
-            if not self.last_batch.is_empty() and not self.last_batch.is_prefill_only:
+            if not self.last_batch.is_empty():
                 if self.running_batch.is_empty():
                     self.running_batch = self.last_batch
                 else:
                     # Merge running_batch with prefill batch
                     self.running_batch.merge_batch(self.last_batch)
 
+        # For prefill-only batch, filter out finished requests since they
+        # won't go through the decode step. This keeps running_batch accurate
+        # for load reporting (num_running_reqs via /get_load).
+        # Runs outside the last_batch block so stale requests are cleaned
+        # even when no new batches arrive (e.g. traffic stops).
+        if self.running_batch.is_prefill_only:
+            self.running_batch.filter_batch()
+
         if self.dllm_config is not None:
             new_batch = self.get_new_batch_dllm()
         else:
@@ -2100,8 +2107,11 @@ def get_next_batch_to_run(self) -> Optional[ScheduleBatch]:
             # Run prefill first if possible
             ret = new_batch
         else:
-            # Run decode
-            if not self.running_batch.is_empty():
+            # Run decode (skip for prefill-only batches)
+            if (
+                not self.running_batch.is_empty()
+                and not self.running_batch.is_prefill_only
+            ):
                 self.running_batch = self.update_running_batch(self.running_batch)
                 ret = self.running_batch if not self.running_batch.is_empty() else None
             else: