Retroactive federal government permanent disability payments

How do retroactive federal government (FERS) retirement permanent disability payments get reported? Received official notice of permanent/final disability from OPM along with my new regular monthly payment amount in November 2020. Prior to this, in October 2020 received retroactive lump sum going back to 2017 first year of disability. My CSA 1099R reports as a gross amount the total payments received - retroactive lump sum, plus total of monthly payments received in 2020. Part of issue maybe my CSA 1099R should have lump sum payment and regular annuity payments reported separately (based on information from back of the CSA 1099).