I have the same problem,
I just received a very late 1099 NEC.
I owed money to the IRS at the end of the ear which I paid with my original return (I owed tax rather than received a refund). When I go in and amend the return and only add the additional 1099 NEC, the calculations from TurboTax become crazy. TurboTax should tell me I need to pay the additional federal tax on the additional 1099 NEC income.
Crazily, it moved all of my estimated tax payments into an overpayment column and now suggest that I should get a large refund even though my income went up with the additional 1099 NEC and actually I owe the tax balance on that NEC.
Please help.
