Ok, I fixed it! I had to go to Delete Forms under Tax Tools. There was a Form 8801 in there (even though it wasn't showing up in my tax return). I deleted it. It appears to have regenerated it and fixed whatever bug it got itself into.
Now it is correctly generating a Form 8801 and I can carryforward my 2021 credit to 2023. Now I won't have to file by mail and manually include a Form 8801.
