diff --git a/nerfacc/data_specs.py b/nerfacc/data_specs.py
index 68181d8..6f6c29a 100644
--- a/nerfacc/data_specs.py
+++ b/nerfacc/data_specs.py
@@ -54,7 +54,7 @@ def _to_cpp(self):
         spec.vals = self.vals.contiguous()
         if self.packed_info is not None:
             spec.chunk_starts = self.packed_info[:, 0].contiguous()
-        if self.chunk_cnts is not None:
+        if self.packed_info is not None:
             spec.chunk_cnts = self.packed_info[:, 1].contiguous()
         if self.ray_indices is not None:
             spec.ray_indices = self.ray_indices.contiguous()