diff --git a/.github/workflows/ci-mobile-ios.yaml b/.github/workflows/ci-mobile-ios.yaml
index db07e6b..f29874f 100644
--- a/.github/workflows/ci-mobile-ios.yaml
+++ b/.github/workflows/ci-mobile-ios.yaml
@@ -122,10 +122,16 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: ${{ inputs.js-timeout-minutes }}
     # cancel-in-progress is TRUE: superseding a push should abandon the older
-    # CI run, which produces no external side effects. `github.job` is in the
-    # key so the three jobs here do not serialise against each other.
+    # CI run, which produces no external side effects.
+    #
+    # The trailing segment is the job id written out literally, NOT
+    # `${{ github.job }}`. In a called workflow that expression evaluates to the
+    # CALLER's job id, so every job here would resolve to the same group and,
+    # with cancel-in-progress on, cancel its own siblings. Observed live in
+    # pr-reviewer: `lint` was cancelled one second in by a sibling and the
+    # aggregator failed on the cancelled dependency.
     concurrency:
-      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-${{ github.job }}
+      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-js
       cancel-in-progress: true
     defaults:
       run:
@@ -194,7 +200,7 @@ jobs:
     runs-on: macos-26
     timeout-minutes: ${{ inputs.ios-timeout-minutes }}
     concurrency:
-      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-${{ github.job }}
+      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-ios-build
       cancel-in-progress: true
     defaults:
       run:
@@ -289,7 +295,7 @@ jobs:
     if: always()
     runs-on: ubuntu-latest
     concurrency:
-      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-${{ github.job }}
+      group: ci-mobile-ios-${{ github.workflow }}-${{ github.ref }}-${{ inputs.working-directory }}-ci
       cancel-in-progress: true
     steps:
       - name: Require all jobs to have succeeded
diff --git a/.github/workflows/ci-python-app.yaml b/.github/workflows/ci-python-app.yaml
index 2151138..cbf58b4 100644
--- a/.github/workflows/ci-python-app.yaml
+++ b/.github/workflows/ci-python-app.yaml
@@ -50,8 +50,14 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     timeout-minutes: 10
+    # The trailing segment of every group in this file is the job id written
+    # out literally, NOT `${{ github.job }}`. In a called workflow that
+    # expression evaluates to the CALLER's job id, so all four jobs here would
+    # resolve to one group and, with cancel-in-progress on, cancel each other.
+    # Observed live in pr-reviewer: `lint` was cancelled one second in by a
+    # sibling and the aggregator failed on the cancelled dependency.
     concurrency:
-      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-${{ github.job }}
+      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-lint
       cancel-in-progress: true
     steps:
       - uses: actions/checkout@v7
@@ -100,7 +106,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     concurrency:
-      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-${{ github.job }}
+      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-test-collect
       cancel-in-progress: true
     steps:
       - uses: actions/checkout@v7
@@ -124,7 +130,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     concurrency:
-      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-${{ github.job }}
+      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-subproject-tests
       cancel-in-progress: true
     steps:
       - uses: actions/checkout@v7
@@ -150,7 +156,7 @@ jobs:
     if: always()
     runs-on: ubuntu-latest
     concurrency:
-      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-${{ github.job }}
+      group: ci-python-app-${{ github.workflow }}-${{ github.ref }}-${{ inputs.source-dirs }}-ci
       cancel-in-progress: true
     steps:
       - name: Require all jobs to have succeeded