Ordinary tax withholding shown in box 4 of the Form 1099-R issued to the estate cannot be passed through on a Schedule K-1. If the estate has a refund due as a result of filing the Form 1041, the estate will have to received the refund and then distribute the refund to the estate beneficiaries during the following estate income-tax year.
(Because of this, one should always request that there be no tax withholding on payments made to an estate.)