[V8] Product_Variant_Default_Code Can not Duplicate Product Template with variants

[bunhin]

To speed up creating new product template with variants, in product form i use duplicate action in the "more" link to copy similar product which have same attribute and attribute value also same in other information then plan to do some edit on certain field only, but the duplicate function generate error message as below:
quote Found unrecognized attribute name in "Variant Reference Mask" end quote

Please help