TurboTax does not get any information from the IRS after you file your tax return, so no one at TT knows about the letter sent to you by the IRS or knows what the IRS changed. It is possible that the IRS found a mistake you made, or that you owe back taxes or child support---which TurboTax would have no way of knowing about. You will have to read the IRS letter very carefully.
I RECEIVED A LETTER FROM THE IRS/STATE
TurboTax does not receive any information from the IRS or your state after your return was filed, so no one at TurboTax knows about a letter you received from the IRS or the state.
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-audit/turbotax-audit-support/L6AcMoN...
https://ttlc.intuit.com/turbotax-support/en-us/help-article/internal-revenue-service/got-cp2000-noti...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
