@LeonardS
Not sure this actually addresses the issue. I have two loans, one originated before 2017, one after. Two 1098's, one for each loan. Even if I change box 2, the average principal balance, and do not override anything the bug remains - the software does not consider the pre-2017 loan if the line D originate before 2017 box is checked (in the step-by-step it's a question that you answer "yes" to).
I don't know how to report a bug. I don't have much time for this, I've already spent days sorting it out. But there is a bug. The software just doesn't handle selling a house with a pre-2017 originated loan and buying a new home with a loan above the 750k limit.
