It sounds like you are running into a Turbotax bug faced by many people, it is combining the mortgage amounts and incorrectly determining that you have exceeded the $750,000 loan maximum for the mortgage interest rate deduction and reducing your deduction accordingly. So for example if you have a $600K home loan that you refinanced in 2020, TurboTax will downscale your deduction assuming you have a $1200K loan (over the limit.)
There is a Turbotax page that tells you to combine the amounts in your various 1098's and enter them as a single 1098, but I don't feel comfortable doing that as the IRS receives all the 1098's from your lenders which means your return would have different information. Here is that page:
https://ttlc.intuit.com/community/loans/help/what-do-i-do-if-i-have-multiple-1098s-from-refinancing-...
BY FAR the best solution I have found is right here (a post by RecoveringEngineer):
https://ttlc.intuit.com/community/tax-credits-deductions/discussion/re-bug-with-refinance-on-a-large...
You can manually adjust your average loan balance in the mortgage interest worksheet (which is not a part of your actual tax return), and your mortgage interest deductions will be calculated correctly in TurboTax and in your return.
