A Google search produced this reference from 1964 that seems to address this situation:
https://ideas.dickinsonlaw.psu.edu/cgi/viewcontent.cgi?article=2367&context=dlra
I would first attempt to get the payer to correct the Form 1099-R to show only 11 months of pension payments. Absent that, I think that the estate would have to deal with this since the repayment was essentially a claim against the estate. It seems that despite section 1341 not addressing this situation, the tax court has allowed the estate to report a claim of right repayment.
