You may be having the same problem a bunch of other people have been having.
https://ttlc.intuit.com/community/tax-credits-deductions/discussion/re-bug-with-refinance-on-a-large...
If, when entering the amounts in Box 2 on your third 1098, the amount added to the amounts in the other Box 2s is in excess of $750,000, TurboTax is improperly combining them and limiting your mortgage interest deduction.
TurboTax has refused to fix this and, instead, is instructing customers to enter information incorrectly and in a manner that violates their own guarantees on max refunds and 100% accuracy in calculations.
Stay tuned for the inevitable lawsuit since this has been a problem for multiple years and TurboTax has almost certainly screwed a lot of its customers out of thousands of dollars because its calculations are, by their own admission, NOT accurate.
