No, you can't do that. It was improper and a mistake to report on your 2018 the 2018 RMD received in 2019. If you did so you must amend your 2018 tax return to remove that extraneous income and report it properly on your 2019 tax return. If the 2018 RMD was a late RMD because the deadline for taking it was December 31, 2018, your amendment must include 2018 Form 5329 and explanation requesting waiver of the 50% excess-accumulation penalty.
