Under Alternative Minnimum Tax for "Uncommon Situations", there's the option:
"I exercised ISOs in 2023, but didn't sell the stock in 2023. Or I sold ISOs in 2023 that I purchased in a previous year."
The latter applies to me. In a prior year, I exercised my ISO shares. Last year, I sold them with a qualifying disposition.
If you continue the flow, two pages later (titled "Did you sell ISOs in 2023 that you purchased in a previous year?") you are prompted to enter the negative adjustment for AMT. No matter what you enter here--it has no impact on the numbers in the AMT taxable income breakdown on the next page.
This seems like a bug. I've contacted live support and was passed around between four different agents--two of whom hung up immediately, the other two seemingly not sharing any context (requiring the entire chat to occur again) and then giving up and quitting the chat themselves.
Separately--I'm using Turbotax Live Premium, which somehow isn't an option the "select a product" dropdowns either?