Is TurboTax double-counting RMD?

I had a distribution from an inherited IRA. I put the amounts from my 1099-R into TurboTax, with the Gross Distribution and Taxable Amount being the same number. That increased my "Federal Tax Due" amount as I expected. When TurboTax asked for the amount of the Required Minimum Distribution, I put the full amount of the distribution, and the Federal Tax Due went up twice as much as when I first input the amount from the 1099-R.

Is that a glitch?

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