I make a module to add invoice pivot table.

report_stock_owner_invoice.py

import logging
import os
from openerp import models, fields, modules, api
from openerp.tools.sql import drop_view_if_exists
import openerp.addons.decimal_precision as dp
_logger = logging.getLogger(__name__)

class ReportStockOwnerInvoice(models.AbstractModel):
    _name = 'report.stock.owner.invoice'
    _auto = False
    invoice_id = fields.Many2one('account.invoice', string='Invoice Reference', readonly=True)
    invoice_state = fields.Selection([
        ('draft','Draft'),
        ('proforma', 'Pro-forma'),
        ('proforma2', 'Pro-forma'),
        ('open', 'Open'),
        ('paid', 'Paid'),
        ('cancel', 'Cancelled'),
        ], string='Invoice Status', readonly=True)
    amount_total = fields.Monetary(string='Invoice Total', readonly=True)
    sale_order_name = fields.Char(string='Order Reference', readonly=True)
    client_order_ref = fields.Char(string='Customer Reference', readonly=True)
    order_state = fields.Selection([
        ('draft', 'Quotation'),
        ('sent', 'Quotation Sent'),
        ('sale', 'Sale Order'),
        ('done', 'Done'),
        ('cancel', 'Cancelled'),
        ], string='Order Status', readonly=True)
    product_id = fields.Many2one('product.product', string='Product', readonly=True)
    categ_id = fields.Many2one('product.category', string='Internal Category', readonly=True)
    quantity = fields.Float(string='Quantity', digits=dp.get_precision('Product Unit of Measure'), readonly=True)
    uom_id = fields.Many2one('product.uom', string='Unit of Measure', readonly=True)
    price_unit = fields.Float(string='Unit Price', readonly=True)
    price_subtotal = fields.Monetary(string='Amount', readonly=True)
    partner_invoice_id = fields.Many2one('res.partner', string='Invoiced Partner', readonly=True)
    partner_shipping_id = fields.Many2one('res.partner', string='Delivery Partner', readonly=True)
    partner_shipping_street = fields.Char('Delivery Street', readonly=True)
    partner_shipping_street2 = fields.Char('Delivery Street2', readonly=True)
    partner_shipping_state_id = fields.Many2one("res.country.state", 'Delivery State', readonly=True)
    partner_shipping_zip = fields.Char('Delivery Zip', readonly=True)
    partner_shipping_city = fields.Char('Delivery City', readonly=True)
    partner_shipping_country_id = fields.Many2one('res.country', 'Delivery Country', readonly=True)
    currency_id = fields.Many2one('res.currency', readonly=True)

    def init(self, cr):
        path_data = os.path.join(modules.get_module_path('stock_owner_account'), 'sql')
        path_view = os.path.join(path_data, 'report_stock_owner_invoice.sql')
        drop_view_if_exists(cr, self._table)
        with open(path_view) as f:
            cr.execute(f.read())

    @api.v7
    def read_group(self, cr, uid, domain, fields, groupby, offset=0, limit=None, context=None, orderby=False,
                   lazy=True):
        if 'price_unit' in fields:
            fields.remove('price_unit')
        if 'amount_total' in fields:
            fields.remove('amount_total')
        return super(ReportStockOwnerInvoice, self).read_group(cr, uid, domain, fields, groupby, offset=0, limit=None,
                                                               context=None, orderby=False, lazy=True)

report_stock_owner_invoice.sql

CREATE OR replace VIEW report_stock_owner_invoice
AS
  SELECT row_number() OVER ()        AS id,
         account_invoice.id          AS invoice_id,
         account_invoice.create_date,
         account_invoice.state       AS invoice_state,
         account_invoice.amount_total,
         account_invoice.currency_id,
         sale_order.name             AS sale_order_name,
         sale_order.client_order_ref,
         sale_order.state            AS order_state,
         account_invoice_line.product_id,
         product_template.categ_id,
         account_invoice_line.quantity,
         account_invoice_line.uom_id,
         account_invoice_line.price_unit,
         account_invoice_line.price_subtotal,
         account_invoice.partner_id  AS partner_invoice_id,
         sale_order.partner_shipping_id,
         partner_shipping.street     AS partner_shipping_street,
         partner_shipping.street2    AS partner_shipping_street2,
         partner_shipping.city       AS partner_shipping_city,
         partner_shipping.state_id   AS partner_shipping_state_id,
         partner_shipping.zip        AS partner_shipping_zip,
         partner_shipping.country_id AS partner_shipping_country_id
  FROM   account_invoice_line
         join account_invoice
           ON account_invoice_line.invoice_id = account_invoice.id
         left join (sale_order_line
                    join sale_order
                      ON sale_order_line.order_id = sale_order.id
                    join res_partner partner_shipping
                      ON sale_order.partner_shipping_id = partner_shipping.id
                    join res_country
                      ON partner_shipping.country_id = res_country.id
                    join sale_order_line_invoice_rel
                      ON sale_order_line_invoice_rel.order_line_id =
                         sale_order_line.id)
                ON sale_order_line_invoice_rel.invoice_line_id =
                   account_invoice_line.id
         join product_product
           ON account_invoice_line.product_id = product_product.id
         join product_template
           ON product_product.product_tmpl_id = product_template.id
         join product_category
           ON product_template.categ_id = product_category.id
         join product_uom
           ON account_invoice_line.uom_id = product_uom.id;

report_stock_owner_invoice.xml

{
    # The human-readable name of your module, displayed in the interface
    'name': "",
    # A more extensive description
    'description': """
    """,
    'author': "Transcontinental",
    # Categories can be used to filter modules in modules listing
    # Check https://github.com/odoo/odoo/blob/master/openerp/addons/base/module/module_data.xml
    # for the full list
    'category': 'Warehouse',
    'version': '0.1',
    # Which modules must be installed for this one to work
    'depends': [
        'account',
    ],
    # data files which are always installed
    'data': [
        'views/report_stock_owner_invoice.xml',
    ],
    # data files which are only installed in "demonstration mode"
    'demo': [],
}

I try to figure what is causing this. Anyone can help?