diff --git a/product.py b/product.py
index 3892bd5..4481138 100644
--- a/product.py
+++ b/product.py
@@ -73,4 +73,13 @@ class Product(metaclass=PoolMeta):
 class Template(metaclass=PoolMeta):
     __name__ = 'product.template'
 
-    positions = fields.One2Many('product_template.position','template', 'Positions')
\ No newline at end of file
+    positions = fields.One2Many('product_template.position','template', 'Positions')
+
+    @classmethod
+    def copy(cls, records, default=None):
+        if default is None:
+            default = {}
+        else:
+            default = default.copy()
+        default.setdefault('positions', None)
+        return super(Template, cls).copy(records, default=default)
\ No newline at end of file