You said that you rolled it over at the end of December 2019 and didn't receive distributions until January 2020.
If you're filing your 2019 taxes, then the rollover is not taxable. It should have code G in the box 7 for rollover. When you take money out of a retirement account, you usually have 60 days in which to put it into another retirement account to avoid taxation of that money.
Since you didn't take money out of the account until January 2020, the withdrawal or distribution should show up until you file your 2021 taxes. You should received a 1099-R for 2020 showing the amount withdrawn in January 2020 along with any other withdrawals from that account.
This is my thinking. Correct me if I'm wrong.
