Impossible to add meta_data to line_items

[boussarilatif]

I am trying to add additional attributes to the line_items before a purchase.
But after the request is done I don't have the information sent in the meta_data attribute
I use woocommerce rest api

//EXAMPLE OF INPUT
{ ...ordersAttributes, line_items: [{ product_id: 12, meta_data: [ { key: 'Size', value: 121 } ] }] }

//EXAMPLE OF OUTPUT
{ ...ordersAttributes, line_items: [{ product_id: 12, meta_data: [] }] }