diff --git a/ci/eval/compare/default.nix b/ci/eval/compare/default.nix
index 0c55b01c7160..b844d45f5902 100644
--- a/ci/eval/compare/default.nix
+++ b/ci/eval/compare/default.nix
@@ -69,7 +69,6 @@ let
     groupByPlatform
     extractPackageNames
     getLabels
-    uniqueStrings
     ;
 
   getAttrs = dir: builtins.fromJSON (builtins.readFile "${dir}/outpaths.json");
@@ -81,7 +80,7 @@ let
   # - values: lists of `packagePlatformPath`s
   diffAttrs = diff beforeAttrs afterAttrs;
 
-  rebuilds = uniqueStrings (diffAttrs.added ++ diffAttrs.changed);
+  rebuilds = diffAttrs.added ++ diffAttrs.changed;
   rebuildsPackagePlatformAttrs = convertToPackagePlatformAttrs rebuilds;
 
   changed-paths =
@@ -110,7 +109,7 @@ let
     );
 
   maintainers = import ./maintainers.nix {
-    changedattrs = lib.unique (map (a: a.packagePath) rebuildsPackagePlatformAttrs);
+    changedattrs = lib.attrNames (lib.groupBy (a: a.name) rebuildsPackagePlatformAttrs);
     changedpathsjson = touchedFilesJson;
   };
 in
diff --git a/ci/eval/compare/maintainers.nix b/ci/eval/compare/maintainers.nix
index 188d8b635729..64025c066f96 100644
--- a/ci/eval/compare/maintainers.nix
+++ b/ci/eval/compare/maintainers.nix
@@ -11,17 +11,13 @@ let
   changedpaths = builtins.fromJSON (builtins.readFile changedpathsjson);
 
   anyMatchingFile =
-    filename:
-    let
-      matching = builtins.filter (changed: lib.strings.hasSuffix changed filename) changedpaths;
-    in
-    (builtins.length matching) > 0;
+    filename: builtins.any (changed: lib.strings.hasSuffix changed filename) changedpaths;
 
-  anyMatchingFiles = files: (builtins.length (builtins.filter anyMatchingFile files)) > 0;
+  anyMatchingFiles = files: builtins.any anyMatchingFile files;
 
-  enrichedAttrs = builtins.map (path: {
-    path = path;
-    name = builtins.concatStringsSep "." path;
+  enrichedAttrs = builtins.map (name: {
+    path = lib.splitString "." name;
+    name = name;
   }) changedattrs;
 
   validPackageAttributes = builtins.filter (
@@ -80,27 +76,16 @@ let
 
   attrsWithModifiedFiles = builtins.filter (pkg: anyMatchingFiles pkg.filenames) attrsWithFilenames;
 
-  listToPing = lib.lists.flatten (
-    builtins.map (
-      pkg:
-      builtins.map (maintainer: {
-        id = maintainer.githubId;
-        packageName = pkg.name;
-        dueToFiles = pkg.filenames;
-      }) pkg.maintainers
-    ) attrsWithModifiedFiles
-  );
-
-  byMaintainer = lib.lists.foldr (
-    ping: collector:
-    collector
-    // {
-      "${toString ping.id}" = [
-        { inherit (ping) packageName dueToFiles; }
-      ] ++ (collector."${toString ping.id}" or [ ]);
-    }
-  ) { } listToPing;
+  listToPing = lib.concatMap (
+    pkg:
+    builtins.map (maintainer: {
+      id = maintainer.githubId;
+      packageName = pkg.name;
+      dueToFiles = pkg.filenames;
+    }) pkg.maintainers
+  ) attrsWithModifiedFiles;
 
+  byMaintainer = lib.groupBy (ping: toString ping.id) listToPing;
 
   packagesPerMaintainer = lib.attrsets.mapAttrs (
     maintainer: packages: builtins.map (pkg: pkg.packageName) packages