Output path comparison

error: while evaluating anonymous function at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/.gc-of-borg-outpaths.nix:39:12, called from undefined position:
while evaluating 'g' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/attrsets.nix:267:19, called from undefined position:
while evaluating anonymous function at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/top-level/release-lib.nix:144:38, called from undefined position:
while evaluating 'isDerivation' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/attrsets.nix:296:18, called from /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/top-level/release-lib.nix:146:10:
while evaluating 'callPackageWith' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:108:35, called from /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/top-level/all-packages.nix:16018:11:
while evaluating 'makeOverridable' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:67:24, called from /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:112:8:
attribute 'version' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/applications/networking/browsers/brave/default.nix:78:5 already defined at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/applications/networking/browsers/brave/default.nix:77:5