I made a mistake in my original 1099-SR form, and had to amend it. I was able to get the Amended return finished, but, on checking it, I found some wild inaccuracies, and had to edit it by hand
I can find no place on the TurboTax web site to report a problem
You're right, it was 1040-X
The problem is that after making the amendment, the value shown on Line 6-Column B (Tax Liability-Net Change) was echoed on Line 22 (OverPaid) and Line 23 (Amount to be Refunded). In my case it was shown as a $418 Refund. When I manually calculated it, I owed $3,744.
Another strange thing is that my Payment Voucher shows the correct Amount, which I will be paying
Don't submit an incorrect Form 1040-X or you will have twice the mess on your hands.