One other thought. If the amount reported on the code-8 2020 Form 1099-R is just the amount of earnings attributable to a 2019 excess deferral corrected in 2020 (which would be reported on a code-P 2020 Form 1099-R), the code-8 amount should probably be reported as Other income (2020 Schedule 1 (Form 1040) line 8 which would appear on MA Schedule X line 4 and Form 1 line 9, although the effect would probably be the same as reporting it on MA Form 1 line 4. I think that only the amount of the excess deferral itself should be treated as wages on the tax return for the year that the excess deferral was made.
