The problem with adding the same value from the other 1098 is that on the California return, the app then adds the two principal balances together, which puts you over the debt limit (if > $1 million). It then does an "adjustment" effectively increasing the tax burden incorrectly. So you have to enter $0 on the 1098 that began in 2019 (assuming it was just due to service transfer on the same loan). Otherwise, it is a bug and TurboTax has to recognize only one value.
When you enter $0, an error does pop up when it does the Federal review. It says that you must enter the beginning principal. I entered $0 again and it takes that and proceeds with the correct calculation.
