Yes, this is an anomaly in TurboTax that is related to how the IRS treats retirement income reported on a 1099-R, which is that all retirement income is subject to RMD, and everything reported on a 1099-R is retirement income.
You were correct to choose 'another type of qualified retirement plan' and enter the total distribution amount from Box 1 (or the taxable amount from Box 2a), as the RMD amount in order to complete your entry. The funds are taxed the same way in either circumstance, and the 4D Code indicates that the amount is ineligible for rollover.
Here's detailed info from the IRS on Pensions and Annuities and more on Form 1099-R.
@roxgentile
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