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
""" Set the rounding of the dozen to 1.0, create a chain of two move for a dozen, the product
        concerned is tracked by serial number. Check that the flow is ok.
        """
        
        self.uom_dozen.rounding = 1
        
        for i in range(1, 13):
            lot_id = self.env['stock.production.lot'].create({
                'name': 'lot%s' % str(i),
                'product_id': self.product2.id,
            })
            self.env['stock.quant']._update_available_quantity(self.product2, self.stock_location, 1.0, lot_id=lot_id)
        
        picking_stock_pack = self.env['stock.picking'].create({
            'location_id': self.stock_location.id,
            'location_dest_id': self.pack_location.id,
            'picking_type_id': self.env.ref('stock.picking_type_internal').id,
        })
        move_stock_pack = self.env['stock.move'].create({
            'name': 'test_link_assign_7',
            'location_id': self.stock_location.id,
            'location_dest_id': self.pack_location.id,
            'product_id': self.product2.id,
            'product_uom': self.uom_dozen.id,
            'product_uom_qty': 1.0,
            'picking_id': picking_stock_pack.id,
        })