RMD question

I received a call today saying that Mom, who died this year, did not take her entire RMD.  I’m told that the IRA account(s) have been transferred to the beneficiaries. How can this be remedied?  Can/should the beneficiaries transfer the RMD shortfall back to the deceased’s IRA (if the broker will allow that)?

Thanks for your help.

Dave Muldowney.

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