Just re-iterating what worked for me
- Wipe out Form 1166, i.e. delete all forms 1166 and 1166AMT manually from return
- Go to interview: select simplified AMT method
- Manually change the date on Form 1166 part 2 column 1, and Form 1166 AMT, part 2, column 1 to 12/30/2020
- Submit
So it's possible to get a return through with the simplified AMT method.
I don't know why this worked: It's entirely possible that the date change from 12/31/2020 to 12/30/2020 is a red herring. There may be a random factor to this, so you may have to just try once a day and see what happens.
