diff --git a/.github/workflows/pr-review-merge-scheduler.yml b/.github/workflows/pr-review-merge-scheduler.yml
index a9bb54f8a..5d7b2f463 100644
--- a/.github/workflows/pr-review-merge-scheduler.yml
+++ b/.github/workflows/pr-review-merge-scheduler.yml
@@ -1068,29 +1068,48 @@ jobs:
             # Compare live refs on every sweep instead of waiting for an age
             # threshold: previous-head checks are never useful merge evidence.
             queue_hygiene_ready=true
-            if ! open_pr_heads_json="$(
+            open_pr_heads_json="{}"
+            if open_pr_refs_tsv="$(
               gh api \
                 -H "Accept: application/vnd.github+json" \
                 "/repos/${repo_full_name}/pulls?state=open&per_page=100" \
                 --paginate \
-                | jq -sc '
-                    add
-                    | map(
-                        select(
-                          .head.repo.full_name != null and
-                          .head.ref != null and
-                          .head.sha != null
-                        )
-                        | {
-                            key: "\(.head.repo.full_name):\(.head.ref)",
-                            value: .head.sha
-                          }
-                      )
-                    | from_entries
+                | jq -sr '
+                    add[]
+                    | [
+                        (if (.head.repo.full_name | type) == "string" then .head.repo.full_name else "" end),
+                        (if (.head.ref | type) == "string" then .head.ref else "" end)
+                      ]
+                    | @tsv
                   '
             )"; then
+              while IFS=$'\t' read -r head_repo head_ref; do
+                if [ -z "$head_repo" ] || [ -z "$head_ref" ]; then
+                  echo "::warning::Current-HEAD cancellation skipped for ${repo_full_name}: an open PR has a malformed head repository or ref. No run will be cancelled from incomplete evidence."
+                  queue_hygiene_ready=false
+                  break
+                fi
+                encoded_head_ref="$(jq -rn --arg value "$head_ref" '$value | split("/") | map(@uri) | join("/")')"
+                if ! live_head_sha="$(
+                  gh api \
+                    -H "Accept: application/vnd.github+json" \
+                    "/repos/${head_repo}/git/ref/heads/${encoded_head_ref}" \
+                    --jq '.object.sha // empty'
+                )" || ! [[ "$live_head_sha" =~ ^[0-9a-fA-F]{40}$ ]]; then
+                  echo "::warning::Current-HEAD cancellation skipped for ${repo_full_name}: live ref ${head_repo}:${head_ref} could not be resolved safely. No run will be cancelled from incomplete evidence."
+                  queue_hygiene_ready=false
+                  break
+                fi
+                open_pr_heads_json="$(
+                  jq \
+                    --arg key "${head_repo}:${head_ref}" \
+                    --arg value "$live_head_sha" \
+                    '. + {($key): $value}' \
+                    <<<"$open_pr_heads_json"
+                )"
+              done <<<"$open_pr_refs_tsv"
+            else
               echo "::warning::Current-HEAD cancellation skipped for ${repo_full_name}: open PR head refs could not be read safely. No run will be cancelled from incomplete evidence."
-              open_pr_heads_json="{}"
               queue_hygiene_ready=false
             fi
             if ! current_default_sha="$(
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cef0acda6..80eb22873 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ this file. The format follows Keep a Changelog, and versioned releases follow
 Semantic Versioning where the repository publishes a release.
 
 ## [Unreleased]
+- Resolve each open PR head through its live Git reference before queue hygiene
+  cancels superseded runs, and fail closed when any ref cannot be read. This
+  prevents a briefly stale pull-request payload from cancelling current-head
+  Checks without adding an arbitrary grace period.
 - Route Strix cross-provider fallbacks to explicit direct-OpenAI models
   (`openai-direct/...`) through the OpenAI inference endpoint instead of
   inheriting a provider-specific primary base: the workflow now provisions
diff --git a/docs/doctoring/queue-hygiene-live-ref-race.md b/docs/doctoring/queue-hygiene-live-ref-race.md
new file mode 100644
index 000000000..775ca39d8
--- /dev/null
+++ b/docs/doctoring/queue-hygiene-live-ref-race.md
@@ -0,0 +1,37 @@
+# Queue hygiene live-reference race
+
+## Incident
+
+On 2026-08-26, LineageWeave PR #667 received a new same-repository head
+`37cc9ab1163f213105d420618e2e8ee69ec6673d`. Its new pull-request workflows
+started, but the organization queue sweep cancelled them while GitHub's open-PR
+payload still exposed the preceding head. The runs were current for the branch
+ref and stale only in the pull-request listing used by the cancellation map.
+
+This was a control-plane defect, not a test failure. Re-running the jobs without
+repairing the comparison source would leave the same race available to every
+repository in the organization.
+
+## Decision
+
+Queue hygiene still enumerates open pull requests to identify eligible head
+repositories and branch names. Before cancelling anything, it now resolves each
+head through GitHub's `Get a reference` endpoint and compares active runs with
+that live Git reference. A missing, inaccessible, or malformed ref makes the
+repository's cancellation pass unavailable; no run is cancelled from partial
+evidence.
+
+No time delay or grace-period heuristic is used. A branch ref is the exact
+commit pointer the check run is meant to validate. The existing rule remains:
+previous-head runs may be cancelled, current-head runs may not.
+
+## Verification
+
+- `uv run --group dev pytest -q tests/test_required_workflow_queue_contract.py`
+- `actionlint .github/workflows/pr-review-merge-scheduler.yml`
+- `git diff --check`
+
+## Reference
+
+GitHub. (n.d.). *REST API endpoints for Git references*. GitHub Docs. Retrieved
+August 26, 2026, from https://docs.github.com/en/rest/git/refs
diff --git a/docs/product-technical-gap-baseline.md b/docs/product-technical-gap-baseline.md
index 252249095..7f797d9e6 100644
--- a/docs/product-technical-gap-baseline.md
+++ b/docs/product-technical-gap-baseline.md
@@ -88,6 +88,7 @@ flowchart LR
 | G-12 | CSAP/SOC 2 통제 목표와 PII masking 대안은 doctoring에 흩어져 있으며 evidence-to-control mapping의 live completeness가 미확인이다 | PII를 마스킹하면 업무가 멈추고, 원문 접근을 허용하면 감사·유출 위험이 커진다 | consent/purpose/access lease, field-level encryption/tokenization, redaction-at-egress, audit/revocation와 CSAP/SOC 2 evidence map을 구현한다 |
 | G-13 | hourly scheduler는 존재하지만 no-op/credential unavailable/queued Checks의 customer next action을 모든 caller가 동일한 receipt로 내는지 미확인이다 | 자동화가 실패해도 운영자가 무엇을 고쳐야 하는지 알 수 없다 | `skipped_credential_unavailable` receipt와 다음 행동 문구를 exact-head Checks로 검증한 뒤 병합하고, bounded receipt schema, retry floor, single-flight, no secret fallback을 모든 caller contract test로 고정한다 |
 | G-14 | release/changelog/version 증거가 각 PR에 분산되고 현재 central repo 보호 main의 release candidate가 명확하지 않다 | 운영자는 어떤 기능이 supportable release인지 확인할 수 없다 | merge 후 release readiness ledger, CHANGELOG, semantic version/tag, rollback/operability evidence를 함께 갱신한다 |
+| G-15 | 조직 큐 정리기가 open-PR payload의 직전 head와 새 branch ref가 잠시 달랐던 LineageWeave #667의 current-head runs를 취소했다 | 정상 Checks가 코드 실패처럼 사라지고 모든 소비 저장소의 병합 루프가 반복 재실행에 갇힌다 | open PR의 repo/ref는 탐색에만 쓰고 취소 판정 SHA는 live Git reference에서 다시 읽는다. ref를 완전하게 읽지 못하면 해당 저장소에서는 아무 run도 취소하지 않는다 |
 
 ## 4. 열린 PR live inventory
 
diff --git a/tests/test_required_workflow_queue_contract.py b/tests/test_required_workflow_queue_contract.py
index 1d79f1daa..78b046918 100644
--- a/tests/test_required_workflow_queue_contract.py
+++ b/tests/test_required_workflow_queue_contract.py
@@ -748,6 +748,13 @@ def test_org_queue_sweep_covers_target_repositories_on_a_heartbeat() -> None:
     assert "ORG_SWEEP_STALE_QUEUE_HOURS" in workflow
     assert "/actions/runs?status=${active_status}&per_page=100" in workflow
     assert "for active_status in queued in_progress" in workflow
+    assert '"/repos/${head_repo}/git/ref/heads/${encoded_head_ref}"' in workflow
+    assert '$value | split("/") | map(@uri) | join("/")' in workflow
+    assert "--jq '.object.sha // empty'" in workflow
+    assert 'open_pr_heads_json="$(\n                  jq' in workflow
+    assert "live ref ${head_repo}:${head_ref} could not be resolved safely" in workflow
+    assert "an open PR has a malformed head repository or ref" in workflow
+    assert "select(.head.repo.full_name != null and .head.ref != null)" not in workflow
     assert '"pull_request" or .event == "pull_request_target"' in workflow
     assert "$current_pr_head == null or .head_sha != $current_pr_head" in workflow
     assert ".head_sha != $current_default_sha" in workflow