Impacted versions:
11.0

I don't know if it is an issue, but I think is strange.

`product_qty` is in unit of `product` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L240
`reserved_availability` is in unit of `stock.move` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L295

`move.product_qty - move.reserved_availability` seems to have no sens, no ?

https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L915
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L917
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L924

thank for your answer

@jco-odoo 
@alnslang 


addons/stock/tests/test_move.py
'location_id': self.pack_location.id,
            'location_dest_id': self.customer_location.id,
            'product_id': self.product1.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 1.0,
        })
        move_pack_cust_2 = self.env['stock.move'].create({
            'name': 'test_link_assign_1_2',
            'location_id': self.pack_location.id,
            'location_dest_id': self.customer_location.id,
            'product_id': self.product1.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 1.0,
        })
        move_stock_pack.write({'move_dest_ids': [(4, move_pack_cust_1.id, 0), (4, move_pack_cust_2.id, 0)]})
        move_pack_cust_1.write({'move_orig_ids': [(4, move_stock_pack.id, 0)]})
        move_pack_cust_2.write({'move_orig_ids': [(4, move_stock_pack.id, 0)]})
        (move_stock_pack + move_pack_cust_1 + move_pack_cust_2)._action_confirm()
        
        move_stock_pack._action_assign()
        self.assertEqual(len(move_stock_pack.move_line_ids), 1)
        move_stock_pack.move_line_ids[0].qty_done = 2.0
        move_stock_pack._action_done()
        
        self.assertEqual(len(move_pack_cust_1.move_line_ids), 1)
        self.assertEqual(len(move_pack_cust_2.move_line_ids), 1)
        move_pack_cust_1.move_line_ids[0].qty_done = 1.0
        move_pack_cust_2.move_line_ids[0].qty_done = 1.0
        (move_pack_cust_1 + move_pack_cust_2)._action_done()
    def test_link_assign_6(self):