TurboTax does not get any information from the IRS or state after you file your tax return. If the IRS found a mistake on your tax return and says you do not get the refund you hoped for, that is an issue between you and the IRS. TurboTax does not know if you entered an incorrect amount or left out some income that should have been entered etc.--there are a variety of reasons why the IRS would change your refund amount that have nothing to do with TurboTax. And you say you do not know why the IRS changed your refund.....wait until you find out more information from the IRS.
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