What does "Deductible Home Mortgage Interest Wks: Your calculations could not be completed. Reference code 8-156-781" mean?

I contacted support and they tried really hard to determine the problem without success. Apparently I am not the first to run into this kind of error where TurboTax is unable to explain the situation so it can be corrected. Support did send several similar cases to me. The next day, I was going to delete the mortgage entries one at a time to see if that helped. The first one I deleted corrected the problem. I then entered the same information and everything was okay. Sine the problem was corrected one the first entry, it is not possible to tell if that was wrong or just deleting any entry would have caused TurboTax to recalculate and correct whatever it had wrong. Another customer reported the same experience.