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 


'location_id': self.stock_location.id,
            'location_dest_id': self.pack_location.id,
            'picking_id': picking.id,
            'product_id': product5.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 100,
        })
        picking.action_confirm()
        picking.action_assign()
        
        
        self.assertEqual(product1_move.state, 'partially_available')
        self.assertEqual(product5_move.state, 'confirmed')
        action = picking.button_validate()
        self.assertEqual(action.get('res_model'), 'stock.immediate.transfer')
        wizard = self.env[(action.get('res_model'))].browse(action.get('res_id'))
        action = wizard.process()
        self.assertTrue(isinstance(action, dict), 'Should open backorder wizard')
        self.assertEqual(action.get('res_model'), 'stock.backorder.confirmation')
        wizard = self.env[(action.get('res_model'))].browse(action.get('res_id'))
        wizard.process()
        backorder = self.env['stock.picking'].search([('backorder_id', '=', picking.id)])
        self.assertEqual(len(backorder), 1.0)
        
        for backorder_move in backorder.move_lines:
            if backorder_move.product_id.id == self.product1.id:
                self.assertEqual(backorder_move.product_qty, 99)
            elif backorder_move.product_id.id == product5.id:
                self.assertEqual(backorder_move.product_qty, 100)
    def test_immediate_validate_4(self):