After doing some more digging, it appears the retention bonus my wife received in 2021 was $6k and not $5k. I apologize for not being accurate with the amount in my initial post. Then in 2022 she was instructed by her employer to repay only $5,541 (i.e., the $6k minus the 6.2% in SS tax ($372) and 1.45% in Medicare tax ($87)), which she did. After she repaid the $5,541 in 2022, the 2021 W-2c my wife received in November of 2022, reflected the $6k reduction in SS and Medicare wages in boxes 3 and 5 and the $372 less of SS tax withheld in box 4 and the $87 less of Medicare tax withheld in box 6.
My question is: Do I need to file a form 843 for the $372 of SS tax and $87 of Medicare tax that was withheld from the initial payment OR not as it appears that this may simply be an internal accounting issue on the part of the employer that they have already addressed? (I understand that I still need to file an amended return for 2022.)
