Determining the Correct Tax Year for a Schedule K-1 Received from an Estate

I received a Schedule K-1 from the estate of a deceased family member.  Printed at the top of the K-1 is "2023" and right below that it says "For calendar year 2023, or tax year"   Below that are boxes for beginning date and end date in mm/dd/yyyy format.  The beginning year is 2023 and the ending year is 2024.  The attorney who is the executor for the estate says that this K-1 is to be filed with the return for tax year 2024.  However, one of my siblings was told by a tax preparer that the 2023 printed at the top of the form dictates that the K-1 should go with tax year 2023, and an amended 2023 return should be done.   WHO IS CORRECT?

 

To complicate matters further we are expecting a 2nd schedule K-1 from the same estate any day now.  This 2nd K-1 will be the final one.  The attorney for the estate tells us that this K-1 will go with our 2025 returns.  I can post the years printed on that K-1 in this thread when I receive it if that helps.

 

Thank you,

glerbnik84