You may need to check the transactions that use the reverse charge. Since this tax form is for bills, there may have been a few invoices that are coded with tax codes incorrectly.
You can check this article as your reference: Applying IGST on invoices. It includes the criteria of taxes to determine transaction rates.
To learn more about what is a GSTR 2 return and its contents, kindly refer to this article: Understanding GSTR 2 form. It contains instructions on where to file the said return in the Where to file GSTR return? section.
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