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 


""" In a receipt picking with two moves, one tracked and one untracked, clicking on
        validate without filling any quantities should displays an UserError as long as no quantity
        done and lot_name is set on the tracked move. Now if the user validates the picking, the
        wizard telling the user all reserved quantities will be processed will NOT be opened. This
        wizard is only opene if no quantities were filled. So validating the picking at this state
        will open another wizard asking for the creation of a backorder. Now, if the user processed
        on the second move more than the reservation, a wizard will ask him to confirm.
        """
        picking_type = self.env.ref('stock.picking_type_in')
        picking_type.use_create_lots = True
        picking_type.use_existing_lots = False
        picking = self.env['stock.picking'].create({
            'location_id': self.supplier_location.id,
            'location_dest_id': self.stock_location.id,
            'picking_type_id': picking_type.id,
        })
        self.env['stock.move'].create({
            'name': 'product1_move',
            'location_id': self.supplier_location.id,
            'location_dest_id': self.stock_location.id,