Yes they must issue a 1099-R but not until Jan 2021 if converted in 2020. That will go on your 2020 tax return next year.
Any conversion after Dec 31, 2019 is a 2020 conversion.
You can *contribute* to a 2019 IRA up to the 2020 due date of the return but conversion are on a calendar year basis.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**