Fix missing draft KV pool transfers in HybridCacheController (#27953)

python/sglang/srt/mem_cache/hybrid_cache/hybrid_cache_controller.py

@@ -410,6 +410,13 @@ class HybridCacheController(BaseHiCacheController):
                 self.io_backend,
                 pool_transfers=resolved_pool_transfers,
             )
+            if self.has_draft and host_indices.numel() > 0:
+                self.mem_pool_host_draft.backup_from_device_all_layer(
+                    self.mem_pool_device_draft,
+                    host_indices,
+                    device_indices,
+                    self.io_backend,
+                )
             finish_event.record()
             self._record_transfer_indices_on_stream(
                 self.write_stream,
@@ -484,6 +491,18 @@ class HybridCacheController(BaseHiCacheController):
                     self.io_backend,
                     pool_transfers=resolved_pool_transfers,
                 )
+                if (
+                    self.has_draft
+                    and host_indices.numel() > 0
+                    and i < self.mem_pool_host_draft.layer_num
+                ):
+                    self.mem_pool_host_draft.load_to_device_per_layer(
+                        self.mem_pool_device_draft,
+                        host_indices,
+                        device_indices,
+                        i,
+                        self.io_backend,
+                    )
                 producer_event.complete(i)
             self._record_transfer_indices_on_stream(
                 self.load_stream,