diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1164567568..de4d684996 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -107,7 +107,22 @@ jobs:
     if: "${{ !cancelled() && needs.classify_pr.outputs.skip_ci != 'true' }}"
     runs-on: "${{ fromJSON(needs.classify_pr.outputs.ubuntu_runner || '[\"ubuntu-latest\"]') }}"
     steps:
+      # On PRs github.ref is the merge ref (refs/pull/N/merge), so the required
+      # checks validate the merge result, not just the PR tip. GitHub builds that
+      # ref asynchronously and it can briefly 404 right after a push, so on
+      # failure we back off and retry the same ref once.
       - name: 'Checkout'
+        id: 'checkout'
+        uses: 'actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd' # v6.0.2
+        continue-on-error: true
+        with:
+          ref: '${{ github.event.inputs.branch_ref || github.ref }}'
+          fetch-depth: 0
+      - name: 'Back off for the merge ref to build'
+        if: "${{ steps.checkout.outcome == 'failure' }}"
+        run: 'sleep 10'
+      - name: 'Checkout (retry on transient ref lag)'
+        if: "${{ steps.checkout.outcome == 'failure' }}"
         uses: 'actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd' # v6.0.2
         with:
           ref: '${{ github.event.inputs.branch_ref || github.ref }}'
@@ -211,9 +226,22 @@ jobs:
             node-version: '22.x'
             upload-coverage: 'false'
     steps:
+      # See the Lint job's checkout: merge ref on PRs, back off and retry once on transient lag.
       - name: 'Checkout'
+        id: 'checkout'
         if: "${{ needs.classify_pr.outputs.skip_ci != 'true' }}"
         uses: 'actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd' # v6.0.2
+        continue-on-error: true
+        with:
+          ref: '${{ github.event.inputs.branch_ref || github.ref }}'
+      - name: 'Back off for the merge ref to build'
+        if: "${{ needs.classify_pr.outputs.skip_ci != 'true' && steps.checkout.outcome == 'failure' }}"
+        run: 'sleep 10'
+      - name: 'Checkout (retry on transient ref lag)'
+        if: "${{ needs.classify_pr.outputs.skip_ci != 'true' && steps.checkout.outcome == 'failure' }}"
+        uses: 'actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd' # v6.0.2
+        with:
+          ref: '${{ github.event.inputs.branch_ref || github.ref }}'
 
       # Self-hosted can't reach nodejs.org reliably; reuse the machine's Node.
       - name: 'Set up Node.js ${{ matrix.node-version }} (hosted)'
@@ -288,9 +316,10 @@ jobs:
     needs:
       - 'classify_pr'
       - 'test'
+    # !cancelled() not always(): don't let a cancelled run hold the concurrency slot here.
     if: |-
       ${{
-        always() &&
+        !cancelled() &&
         needs.classify_pr.outputs.skip_ci != 'true' &&
         github.event_name == 'pull_request' &&
         github.event.pull_request.head.repo.full_name == github.repository