Amended Mo does not affect federal

I am amending my 2023 Missouri state taxes because I forgot to enter a subtraction (from income). This only affect state taxes, not federal. When trying to complete the amendment, it is hung up on requiring a date on line 47D of the MO-1040. The reason is D, correction other than A, B, or C. It reads "Enter date of federal amended return, if filed". Well, one wasn't filed, but it is insisting on a date.

I thought about just printing the form and mailing it without completing it, but it kind of sounds like MO expects you to amend federal.

-Do I have to file a federal, even if it is unaffected?

-If not, how can I work around this date TurboTax is requiring?

-If I can just print and mail, which forms will I need to mail? Thanks in advance.

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