2018 Amended Return not processed, IRS sent payment back plus interest

I amended my 2018 return in 2019 (payment included). Filed my 2019 return after sending in amended return.  IRS has not processed the 2018 amended return and sent the payment plus interest back.  IRS sent 1099-INT for 2020.  Do I wait to file my 2020 return? Do I have to include the interest?