diff --git a/chebai_graph/preprocessing/properties.py b/chebai_graph/preprocessing/properties.py
index 21d8342..543a344 100644
--- a/chebai_graph/preprocessing/properties.py
+++ b/chebai_graph/preprocessing/properties.py
@@ -155,5 +155,5 @@ def get_property_value(self, mol: Chem.rdchem.Mol):
         features_normalized = generator_normalized.processMol(
             mol, Chem.MolToSmiles(mol)
         )
-        np.nan_to_num(features_normalized, copy=False)
+        features_normalized = np.nan_to_num(features_normalized)
         return [features_normalized[1:]]