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 


""" Test that editing a done stock move line linked to an untracked product correctly and
        directly adapts the transfer. In this case, we edit the sublocation where we take the
        product to another sublocation where a product is NOT available because it has been reserved
        by another move.
        """
        shelf1_location = self.env['stock.location'].create({
            'name': 'shelf1',
            'usage': 'internal',
            'location_id': self.stock_location.id,
        })
        shelf2_location = self.env['stock.location'].create({
            'name': 'shelf1',
            'usage': 'internal',
            'location_id': self.stock_location.id,
        })
        self.env['stock.quant']._update_available_quantity(self.product1, shelf1_location, 1.0)
        self.env['stock.quant']._update_available_quantity(self.product1, shelf2_location, 1.0)
        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product1, self.stock_location), 2.0)
        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, shelf2_location), 1.0)
        move1 = self.env['stock.move'].create({
            'name': 'test_edit_moveline_1',
            'location_id': self.stock_location.id,
            'location_dest_id': self.customer_location.id,
            'product_id': self.product1.id,
            'product_uom': self.uom_unit.id,
            'product_uom_qty': 1.0,
        })