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 


if any(move.state not in ('draft', 'cancel') for move in self):
            raise UserError(_('You can only delete draft moves.'))
        # 
        self.mapped('move_line_ids').unlink()
        return super(StockMove, self).unlink()
    def _prepare_move_split_vals(self, qty):
        vals = {
            'product_uom_qty': qty,
            'procure_method': 'make_to_stock',
            'move_dest_ids': [(4, x.id) for x in self.move_dest_ids if x.state not in ('done', 'cancel')],
            'move_orig_ids': [(4, x.id) for x in self.move_orig_ids],
            'origin_returned_move_id': self.origin_returned_move_id.id,
            'price_unit': self.price_unit,
        }
        if self.env.context.get('force_split_uom_id'):
            vals['product_uom'] = self.env.context['force_split_uom_id']
        return vals
    def _split(self, qty, restrict_partner_id=False):