1040 X

Ive completed my amended tax return for 2020 now that my return has been received and accepted by the IRS.

There is an Issue I have on the1040 X form in a section labeled "original 2020 return payments smart worksheet".

It is claiming in section C a large payment made to the IRS that I am not aware of making.Additional tax paid paid after return was filed?? where in the walk through would this credit on a payment be listed so I can review. I would like to submit this amended return but I made no payment with my return when filed . I did ,however notice,  the amount I owed the IRS was substantially lower a short while after I initially filed. so now I think this worksheet assumes I made an initial IRS payment or I inadvertently listed this amount by error. I wonder also if this applied credit/payment is due to an update in the tax law.