Duplicate content for existing products

Some of the product’s attributes do not need to be translated, e.g weight.
I added translated product according to this doc https://polylang.pro/doc/duplicating-content-across-post-translations/
Seems content duplication only works when creating non-existing translation.
If the product is already translated, and I add some new attributes, then newly added attributes value are not duplicated.
For example I have ProductA_english, and ProductA_french. Now I need to add a new attribute to all products, so I set ProductA_english attribute_new = “some value”. How can I duplicate it to ProductA_french.