After finally getting my refund shorted, I also got letter from IRS stating miscalculation regarding Recovery Rebate Credit. Wouldn't Turbot tax have picked this up?

[xmasbaby0]

TurboTax has no way to know whether you received the 1st and/or 2nd EIP payments.   When you prepared your tax return you were asked if you had received those payments.   If you said you did not receive the payment(s) then the stimulus payment was put on line 30 of your tax return as a recovery rebate credit.  The IRS cross checks every return with an amount on line 30.  If the IRS sees that they already issued the EIP payment(s) to you then they adjust your refund.

Check your IRS account---does the IRS say they sent you a payment that you did not receive?  If so you can ask for a trace to be put on the payment.

https://www.irs.gov/payments/view-your-tax-account

If you were issued a payment and have not received it, see How do I request a payment trace to track my first or second Economic Impact Payments?

[fanfare]

Did you file status MFJ or something else ?