Just got off the phone with Intuit support on this. The rep was actually very helpful and cordial. Here's what I learned:
1) You currently have several options; check how each one affects your refund/bill.
a) Take a deduction instead of a credit.
b) State that you have no carryforward/carryback credits (or choose not to use them this year).
c) Do (a) or (b) now and file electronically, then file an amended return via mail on March 31 to handle the difference. You may not need to file an amended state return if you go this route.
d) Just wait till March 31 and file via mail.
2) The rep could not answer if taking a deduction this year, then a credit next year, would be a problem, since your prior year return would not mention the carryforward/carryback schedule.
3) If you go with one of the E-file options listed above, first be sure to record, outside of TurboTax, your carryover schedule as reported by TurboTax. As soon as you elect one of these routes in Interview, that schedule will be erased, and it can be complicated to recalculate. Ideally, go to your 1116 form in TurboTax and record both your 2021 and 2022 numbers, prior to selecting in Interview. (You can probably ignore the AMT schedule if you don't do alternative minimum, but it's best to record both.)
4) Intuit upper management has taken notice of the volume of complaints on 1116 and 1116 Schedule B. In fact, there have been so many 1116-related refund requests, those refunds are backlogged. The rep said there were no promises but "there's a good chance they'll change their minds and start supporting the form after all". I'm waiting a few days to find out.
