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
""" Send products tracked by lot to a customer. In your stock, there are tracked and
        untracked quants. Two moves lines should be created: one for the tracked ones, another
        for the untracked ones.
        """
        lot1 = self.env['stock.production.lot'].create({
            'name': 'lot1',
            'product_id': self.product3.id,
        })
        self.env['stock.quant']._update_available_quantity(self.product3, self.stock_location, 2)
        self.env['stock.quant']._update_available_quantity(self.product3, self.stock_location, 3, lot_id=lot1)
        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product3, self.stock_location), 5.0)
        
        move1 = self.env['stock.move'].create({
            'name': 'test_in_1',
            'location_id': self.stock_location.id,
            'location_dest_id': self.customer_location.id,
            'product_id': self.product3.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 5.0,
        })
        move1._action_confirm()
        move1._action_assign()
        self.assertEqual(len(move1.move_line_ids), 2)