I discovered a similar issue when I was about to submit my taxes this year (on PC version, not MAC). We had a refinanced loan and a HELOC and despite answering all the questions correctly (no cash taken out of the refinanced loan, and more money spent on the home using the HELOC than is outstanding on the HELOC), it would only deduct a small amount of the the interest from the refinanced loan, while deducting all the interest on the HELOC loan. I spoke with 2 different diligent Turbotax agents on 2 different evenings, the second one for an hour. We tried correcting the worksheet and the step-by-step questions several times and initially it made no difference. Eventually one of the times we corrected the worksheet for the refinanced loan and said that there was no cash taken out (which was always true), and we zeroed the amount the program had filled in (which was the amount taken out on the initial HELOC loan, which was irrelevant), the proper amount of interest (all of it) was reflected in the worksheet and on schedule A, and I got the extra $4000 I was entitled to. It looks like I have the same issue for 2020 and didn't notice, so I will likely have to file an amended return for last year if I can get the program to do it right. It's always possible that I filled something out wrong, but if I did, the Turbotax agents and I couldn't find what that was.
