diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f3293be7..bcb49bd8 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -69,11 +69,11 @@ jobs:
 #    name: Run all tests and organize all test reports
     uses: ./.github/workflows/rw_run_all_test_and_record.yaml
     with:
-      # PRs run ubuntu-only to trim the 4-OS matrix; push/scheduled/release keep the full list.
+      # PRs run ubuntu-only to trim the 3-OS matrix (macos-14 dropped: GitHub reports "macos-14-arm64-us-default is not supported", AAASM-6458); push/scheduled/release keep the full list.
       operating-systems: >-
         ${{ github.event_name == 'pull_request'
             && '["ubuntu-latest"]'
-            || '["ubuntu-latest", "ubuntu-22.04", "macos-latest", "macos-14"]' }}
+            || '["ubuntu-latest", "ubuntu-22.04", "macos-latest"]' }}
     secrets:
       codecov_token: ${{ secrets.CODECOV_TOKEN }}
       sonar_token: ${{ secrets.SONAR_TOKEN }}
diff --git a/.github/workflows/rw_build_and_test.yaml b/.github/workflows/rw_build_and_test.yaml
index 4cb361b1..c24120e5 100644
--- a/.github/workflows/rw_build_and_test.yaml
+++ b/.github/workflows/rw_build_and_test.yaml
@@ -9,10 +9,10 @@ on:
         required: false
         default: false
       operating-systems:
-        description: "JSON array string of runner OSes for the test matrix. Callers pass [\"ubuntu-latest\"] for PRs and the full 4-OS list for push/scheduled/release."
+        description: "JSON array string of runner OSes for the test matrix. Callers pass [\"ubuntu-latest\"] for PRs and the full 3-OS list for push/scheduled/release."
         type: string
         required: false
-        default: '["ubuntu-latest", "ubuntu-22.04", "macos-latest", "macos-14"]'
+        default: '["ubuntu-latest", "ubuntu-22.04", "macos-latest"]'
     secrets:
       e2e_test_api_token:
         description: "Set the Slack bot token for end-to-end test."
diff --git a/.github/workflows/rw_run_all_test_and_record.yaml b/.github/workflows/rw_run_all_test_and_record.yaml
index a459cd4c..3dd76782 100644
--- a/.github/workflows/rw_run_all_test_and_record.yaml
+++ b/.github/workflows/rw_run_all_test_and_record.yaml
@@ -12,7 +12,7 @@ on:
         description: "JSON array string of runner OSes for the test matrix. Forwarded to rw_build_and_test."
         type: string
         required: false
-        default: '["ubuntu-latest", "ubuntu-22.04", "macos-latest", "macos-14"]'
+        default: '["ubuntu-latest", "ubuntu-22.04", "macos-latest"]'
     secrets:
       e2e_test_api_token:
         description: "Set the Slack bot token for end-to-end test."