@bwcathe , only thing I can think of is that SSA must be aware that you are the trustee or the sole beneficiary of your mother. If you have already filed the last/ final return for your mother, you can amend that return showing the SSA-1099 and include a note explaining that this income is in respect of the decedent and therefore part of the "closed" estate. Else , you just accept the amount and include it on your return ( and pay any taxes due ).
