This field:
https://github.com/odoo/odoo/blob/625a648f227325468981a9e4a51e80b44132a45f/addons/stock/models/stock_move_line.py#L40

Allways shows the same value as create_date.

Could it be defined as stock.move related field?

Should it be written here?
https://github.com/odoo/odoo/blob/3c0337673385876922da95296e70a0b7b728f275/addons/stock/models/stock_move.py#L1048

@Tecnativa
""" This method is called during a move's `action_done`. It'll actually move a quant from
        the source location to the destination location, and unreserve if needed in the source
        location.
        This method is intended to be called on all the move lines of a move. This method is not
        intended to be called when editing a `done` move (that's what the override of `write` here
        is done.
        """
        
        
        
        
        
        ml_to_delete = self.env['stock.move.line']
        for ml in self:
            qty_done_float_compared = float_compare(ml.qty_done, 0, precision_rounding=ml.product_uom_id.rounding)
            if qty_done_float_compared > 0:
                if ml.product_id.tracking != 'none':
                    picking_type_id = ml.move_id.picking_type_id
                    if picking_type_id:
                        if picking_type_id.use_create_lots:
                            
                            
                            
                            if ml.lot_name and not ml.lot_id:
                                lot = self.env['stock.production.lot'].create(
                                    {'name': ml.lot_name, 'product_id': ml.product_id.id}
                                )
                                ml.write({'lot_id': lot.id})