You should not be getting that question. Please try to delete the Form 1099-R entries and reenter it. If you are using TurboTax Online delete your cookies and clear you cache before entering the Form 1099-R again.
Please try the following workaround when you re-enter the form.
Workaround for code 7D, omit the code 7 and enter only the code D.
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I have the same issue (but with 4D), and during a phone call with a TurboTax expert, she did not recommend omitting the "4" because the entry would differ from the 1099-R submitted to the IRS, and could trigger an audit. I was told there was a fix in progress (I use the online version).