Another part of the answer: estate distributions made before the end of the tax year(probably fiscal year) and/or within 2 1/2(?) months of year-end are taxable to the recipients/beneficiaries of the money.

That way the estate, with a much higher tax bracket, can pass the income through to the lower taxed benes. IE, estate with $100,400 of taxable income owes $34,011.

If the 1099-R has federal withholding, that can be refunded, but not passed through to the benes. Benes would have to pay tax then wait for the estate's refund.

Not naming beneficiaries on retirement accounts is probably the most costly mistake a TP can make.

(ps I am not taking into consideration any charities named as beneficiaries.)