I am late to the parade and I may have misread something here, but this is my take:

1. A nondeductible IRA was made in 2025 for 2024 - Have you read the instructions for 8606?

2. Look at the bold item between lines 3 & 4 

e.g. Everything from that line up to line 14 should be blank cuz the answer is NO and you skip Part I

The Conversion is in 2025 and will be shown on that return and this 2024 return is establishing the basis to show on the 2025 form. 

P.S. You keep saying "wrong Form 8606" do you mean "incorrectly prepared 8606" I first read the statement and thought it was doing a form for the spouse and not the taxpayer. 

I think in this case the taxpayer may be paying top dollar for a tax preparer and they are one being shorted. Also Support apparently did not clearly get the information needed to tell you that YOU are wrong and the program is correct.  Sorry if this sounds offensive, but I have had a bad year and have become more reactive to things then I have in the past. Please let me know if I am wrong.