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
move1.move_line_ids.qty_done = 0
        self.assertEqual(move1.product_uom_qty, 0.0)
        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product1, shelf1_location), 1.0)
        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product1, self.stock_location), 1.0)
    def test_edit_done_move_line_10(self):
        """ Edit the quantity done for an incoming move shoudld also remove the quant if there
            are no product in stock.
        """
        
        move1 = self.env['stock.move'].create({
            'name': 'test_edit_moveline_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,
        })
        move1._action_confirm()
        move1._action_assign()
        move1.move_line_ids.qty_done = 10
        move1._action_done()
        quant = self.env['stock.quant']._gather(self.product1, self.stock_location)
        self.assertEqual(len(quant), 1.0)
        
        move1.move_line_ids.qty_done = 0
        quant = self.env['stock.quant']._gather(self.product1, self.stock_location)
        self.assertEqual(len(quant), 0.0)
        self.assertEqual(move1.product_uom_qty, 0.0)
    def test_edit_done_move_line_11(self):