@jllatimer wrote:
Would the kind folks at Intuit like to help me figure out why the software finds no error but the IRS does?
The threshold questions would involve whether the IRS made an error in their calculation or whether there was an input error.
Regardless, if you cannot resolve this on your own by reviewing your 2018 return for an input error, then you will have to contact Support (link below). One way Support can provide further assistance is by having you send them a sanitized (all identifying information removed) copy of your 2018 return.
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
