Mrohwf24, there is nothing that needs to be corrected in regard to your 2020 Form 1099-R. The reporting of just the $5,400 return of contribution on this form is correct because that's the only one that occurred in 2020. The return of contribution that you obtained in January 2021 will be reported on a code PJ 2021 Form 1099-R next year.
The gains present in box 2a of that code PJ form 1099-R that you will receive next year still need to be reported on your 2020 tax return. You can do that by entering this Form 1099-R as if you have already received it and include in your explanation statement the details of both of these returns of contribution. When entering that 1099-R into 2020 TurboTax the code P will cause TurboTax to ask if it's a 2020 or a 2021 Form 1099-R, to which you must indicate that it's a 2021 Form 1099-R. Box 1 needs to have the gross amount distributed (the amount returned plus gains) and box 2a must show only the gains.
