@DanaB27 - Hi Dana, thank you for your explanation - it was very helpful. If you could be so kind, I could use your advice for a similar situation I am in.
I'm 36 years old and I overcontributed to my 401K in 2020 (I changed employers) so I reached out to my current plan administrator (same administrator as in 2020) to withdraw the excess contribution in 2021. They sent me a check, which included my excess contribution + earnings - 10% early withdraw penalty for federal and state.
Do you recommend waiting until I receive my 2021 1099-R and amending my 2020 return then or creating a 1099R and reporting the excess 401K contribution in 2020?
