Entering 2 mortgage interest deductions is leading to strange outcome in Turbotax

I have two mortgages interest deds, when I enter both (20k + 2k) the deduction seems to be halved (total ded = ~ 12.5k). When i enter just one ded (20k), total says 20k, Why?

 

The bigger deduction (20K) is from  a 550k loan from 2017, the smaller deduction (2k) is from a 870k from 2020.