When issuing the invoices to customers each line on the invoice has a "H" for a tax.
It happens, when it is busy that, by mistake "H" is deleted by the employee and tax is not assigned to that line. When filing the HST to government, filing is incorrect due to this error. Your Tax report comes close to this idea but needs additional column "INVOICE NET AMOUNT" not just amount to which HST has been applied in order to figure out among hundreds of invoices on which invoice and its line this error has happened in order to be fixed before HST filing is done.