I will summarize what I think should be done by TurboTax concerning this issue.
If it is true that amending a Wisconsin state return is not supported, then the following link should not indicate that it is supported: https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/e-file-ame[product key remove...
If it is true that amending a Wisconsin state return is not supported, then the online TT UI should not allow the user to attempt to amend the state return. I was able to file my amended return (and it was rejected for not being filled out correctly).
If amending a Wisconsin state return is supposed to be supported, then TT needs to determine why it did not work correctly when I tried it. I did not receive a "Fix my return" button to select. Instead I am locked out of accessing my 2020 state return online. This is a bug that should be fixed.
Thanks.
