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/models/stock_move.py
uom_quantity_back_to_product_uom = self.product_uom._compute_quantity(uom_quantity, self.product_id.uom_id, rounding_method='HALF-UP')
            rounding = self.env['decimal.precision'].precision_get('Product Unit of Measure')
            if float_compare(quantity, uom_quantity_back_to_product_uom, precision_digits=rounding) == 0:
                vals = dict(vals, product_uom_qty=uom_quantity)
            else:
                vals = dict(vals, product_uom_qty=quantity, product_uom_id=self.product_id.uom_id.id)
        if reserved_quant:
            vals = dict(
                vals,
                location_id=reserved_quant.location_id.id,
                lot_id=reserved_quant.lot_id.id or False,
                package_id=reserved_quant.package_id.id or False,
                owner_id =reserved_quant.owner_id.id or False,
            )
        return vals
    def _update_reserved_quantity(self, need, available_quantity, location_id, lot_id=None, package_id=None, owner_id=None, strict=True):
        """ Create or update move lines.
        """
        self.ensure_one()
        if not lot_id:
            lot_id = self.env['stock.production.lot']
        if not package_id:
            package_id = self.env['stock.quant.package']
        if not owner_id:
            owner_id = self.env['res.partner']
        taken_quantity = min(available_quantity, need)
        # 
        # 
        # 
        #