Your questions is lacking essential details. My guess is that the decedent died in 2024, that the decedent completed only part of the 2024 RMD, and that you as beneficiary completed, or will complete, the 2024 RMD in 2025. My reply is based on this guess:
Under these circumstances, upon the death of the decedent responsibility to complete the remaining portion of the 2024 RMD moved to the beneficiary(s). The beneficiary(s) have until December 31, 2025 to complete the 2024 RMD, so no 2024 Form 5329 needs to be filed with either the decedent's final income tax return or the beneficiary(s) tax return(s) as long as the 2024 RMD is completed by the end of 2025.
When preparing the decedent's final tax return, indicate that the amount required to be distributed was only the amount actually distributed in 2024.
Nothing about this goes on the beneficiary(s) 2024 tax return(s) if no distributions were paid to the beneficiary(s) from the inherited IRA in 2024.
The beneficiary(s) will report RMDs taken in 2025 on their 2025 tax return(s).