I am having the same issue where the check box for "Paid Minnesota alternative minimum tax in a prior year" is automatically checked on the Minnesota Credits page. I deselect it and check none of the above and move on to the next page but the next page is titled "Minnesota Alternative Minimum Tax" and leads to the next page asking questions about form 6251 (which I have never filled out). When I go back to the Minnesota Credits page, the box for "Paid Minnesota alternative minimum tax in a prior year" is checked again and the "None of the above" box is now unchecked.
I tried deleting the M1MTC form but that has not fixed the issue. I have filed through TurboTax online since 2015 and have not ever run into this issue. It seems to be a bug with the Minnesota Credits page of the filing process.
