The additional money would have to be reported as income in 2019.
If this money was needed to satisfy the RMD you would ask for a waiver of the penalty and tell them due the oversight it was taken by April 1st of the following year and IRS will waive the penalty.
Assuming that 2018 was not your first RMD year, the late
distribution must be made before filing Form 5329 to request a waiver of
the 50% excess accumulation penalty. This distribution made in 2019
will be reportable on your 2019 tax return along with the 2019 RMD that
needs to be taken before the end of the year.
