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 


""" Increase the initial demand on a receipt picking, the system should automatically
        reserve the new quantity.
        """
        picking = self.env['stock.picking'].create({
            'location_id': self.supplier_location.id,
            'location_dest_id': self.stock_location.id,
            'picking_type_id': self.env.ref('stock.picking_type_in').id,
        })
        move1 = self.env['stock.move'].create({
            'name': 'test_transit_1',
            'location_id': self.supplier_location.id,
            'location_dest_id': self.stock_location.id,
            'product_id': self.product1.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 10.0,
            'picking_id': picking.id,
        })
        picking._autoconfirm_picking()
        self.assertEqual(picking.state, 'assigned')
        move1.product_uom_qty = 12
        self.assertEqual(picking.state, 'assigned')
    def test_initial_demand_4(self):