diff --git a/.github/workflows/thank-you-note.lock.yml b/.github/workflows/thank-you-note.lock.yml
index 4a33dbf692c..3b84610f858 100644
--- a/.github/workflows/thank-you-note.lock.yml
+++ b/.github/workflows/thank-you-note.lock.yml
@@ -111,6 +111,9 @@ jobs:
           echo "Git configured with standard GitHub Actions identity"
       - name: Checkout PR branch
         id: checkout-pr
+        # On merged/closed PRs the head branch may be deleted, so a failed
+        # checkout must not fail the job (the agent still posts the thank-you note).
+        continue-on-error: true
         if: |
           github.event.pull_request
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0