diff --git a/src/pyedb/dotnet/edb_core/padstack.py b/src/pyedb/dotnet/edb_core/padstack.py
index f7b5e851b2..9d996b7ea2 100644
--- a/src/pyedb/dotnet/edb_core/padstack.py
+++ b/src/pyedb/dotnet/edb_core/padstack.py
@@ -1859,8 +1859,9 @@ def reduce_via_in_bounding_box(self, bounding_box, x_samples, y_samples, nets=No
                     for _x, _y in zip(x_grid.ravel(), y_grid.ravel())
                 }
 
+                all_instances = self.instances
                 for item in padstacks_inbox:
                     if item not in to_keep:
-                        self.instances[item].delete()
+                        all_instances[item].delete()
 
                 return True