@LenaH The IRS clearly ruled that for home acquisition mortgages acquired prior to 2017, the mortgage interest deduction limit is $1,000,000 plus the $100,000 home equity debt limit (i.e. an effective limit of $1.1 million total), when the mortgage acquisition debt exceeds $1 million and the FMV of the home is at least as much as well. See IRS Revenue Ruling 2010-25 here: https://www.irs.gov/pub/irs-drop/rr-2010-25.pdf
The federal tax law changes for TY2018 suspended the extra $100,000 home equity debt limit for the mortgage interest deduction federal taxes, but California tax law does not conform to that change (as the Schedule CA instructions you linked explain). So the effective mortgage interest deduction limit for California state taxes remains $1.1 million for home acquisition mortgages dated prior to 2017.
In any case, the much more important point here is that TurboTax Online does not (and has never) performed the California state adjustment calculation here — TurboTax Online specifically requires the user to manually enter the mortgage interest deduction amount they want to use for California state taxes in the UI (see the screenshot I provided earlier in this thread). And prior to TY2022, that value was correctly used and reflected on the generated tax forms, but starting in TY2022 that no longer works. This is clearly a basic logic bug in the TurboTax Online software, where the user-entered value is being completely ignored and never used, and there is no way to work around this bug.
