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
move2._action_assign()
        move2.move_line_ids.lot_id = lot2
        move2.move_line_ids.qty_done = 1
        move2._action_done()
        initial_in_date_lot2 = self.env['stock.quant'].search([
            ('location_id', '=', self.stock_location.id),
            ('product_id', '=', self.product3.id),
            ('lot_id', '=', lot2.id),
        ]).in_date
        
        quant_lot1 = self.env['stock.quant'].search([
            ('location_id', '=', self.stock_location.id),
            ('product_id', '=', self.product3.id),
            ('lot_id', '=', lot1.id),
        ])
        from datetime import datetime, timedelta
        initial_in_date_lot1 = datetime.now() - timedelta(days=5)
        quant_lot1.in_date = initial_in_date_lot1
        
        move3 = self.env['stock.move'].create({
            'name': 'test_in_date_1',
            'location_id': self.stock_location.id,
            'location_dest_id': self.pack_location.id,
            'product_id': self.product3.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 1.0,
        })
        move3._action_confirm()
        move3._action_assign()
        move3.move_line_ids.qty_done = 1