diff --git a/src/queue/processors.ts b/src/queue/processors.ts
index 1d019a26a..43cb99447 100644
--- a/src/queue/processors.ts
+++ b/src/queue/processors.ts
@@ -3787,7 +3787,21 @@ async function wakeOverCapSiblingPullRequests(
 ): Promise<void> {
   await Promise.all(
     siblingPrNumbers.map(async (prNumber) => {
-      const key = `contributor-cap-wake:${repoFullName.toLowerCase()}#${prNumber}`;
+      // #5385-sentry (GITTENSORY-1D): keyed by the sibling's CURRENT head SHA (not just its number) and held for
+      // a much longer cooldown than the 60s CI-completion-burst window CI_COALESCE_WINDOW_SECONDS was designed
+      // for -- a repeat over-cap discovery for an UNCHANGED head within the cooldown has nothing new to learn
+      // from a fresh full re-review; a new commit changes the head SHA and naturally resets the guard, mirroring
+      // the identical "a new commit resets the CI-stuck-finalize guard" idiom used above (#orb-ci-stuck-repeat).
+      // Without this, a contributor who repeatedly opens (and has auto-closed) near-duplicate PRs re-triggers
+      // THIS sibling's full review/gate republish every time the cap is recomputed, even though nothing about
+      // the sibling itself changed -- confirmed live: one PR published 27 redundant review surfaces in 2 hours
+      // this way, driven entirely by a different PR's open/close churn. Fail open to the tighter, headSha-less
+      // key on a lookup miss (PR not found locally) rather than skip the wake outright.
+      const sibling = await getPullRequest(env, repoFullName, prNumber).catch(() => null);
+      const key = sibling?.headSha
+        ? `contributor-cap-wake:${repoFullName.toLowerCase()}#${prNumber}#${sibling.headSha}`
+        : `contributor-cap-wake:${repoFullName.toLowerCase()}#${prNumber}`;
+      const cooldownSeconds = sibling?.headSha ? Math.round(AI_REVIEW_NON_CACHEABLE_RETRY_COOLDOWN_MS / 1000) : CI_COALESCE_WINDOW_SECONDS;
       if (await getTransientKey(env, key)) return;
       try {
         await env.JOBS.send({
@@ -3808,7 +3822,7 @@ async function wakeOverCapSiblingPullRequests(
         );
         return; // do NOT claim — a later discovery should retry the enqueue
       }
-      await putTransientKey(env, key, "1", CI_COALESCE_WINDOW_SECONDS);
+      await putTransientKey(env, key, "1", cooldownSeconds);
     }),
   );
 }
diff --git a/test/unit/queue-3.test.ts b/test/unit/queue-3.test.ts
index 1436bbc9c..9c05798a2 100644
--- a/test/unit/queue-3.test.ts
+++ b/test/unit/queue-3.test.ts
@@ -4310,7 +4310,9 @@ describe("queue processors", () => {
     });
     // Pre-seed the coalescing key for PR56 exactly as wakeOverCapSiblingPullRequests itself would after a
     // first, already-successful enqueue — proving the SECOND discovery within the window skips re-enqueueing.
-    await env.SELFHOST_TRANSIENT_CACHE?.set("contributor-cap-wake:jsonbored/gittensory#56", "1", 60);
+    // #5385-sentry (GITTENSORY-1D): keyed by PR56's own head SHA ("f56", upserted below) since the sibling
+    // wake now resolves and includes it, not just the bare PR number.
+    await env.SELFHOST_TRANSIENT_CACHE?.set("contributor-cap-wake:jsonbored/gittensory#56#f56", "1", 60);
     await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 54, title: "Farmer PR zero", state: "open", user: { login: "farmer99" }, head: { sha: "f54" }, labels: [], body: "w" });
     await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 56, title: "Farmer PR two (already over cap)", state: "open", user: { login: "farmer99" }, head: { sha: "f56" }, labels: [], body: "y" });
     await upsertRepositorySettings(env, {
@@ -4413,8 +4415,159 @@ describe("queue processors", () => {
       }),
     ).resolves.not.toThrow();
 
-    // The coalescing key was NOT claimed (enqueue failed), so a later discovery can still retry.
-    expect(await env.SELFHOST_TRANSIENT_CACHE?.get("contributor-cap-wake:jsonbored/gittensory#56")).toBeNull();
+    // The coalescing key was NOT claimed (enqueue failed), so a later discovery can still retry. Keyed by
+    // PR56's own head SHA ("f56", upserted above) — see the coalescing test's identical note.
+    expect(await env.SELFHOST_TRANSIENT_CACHE?.get("contributor-cap-wake:jsonbored/gittensory#56#f56")).toBeNull();
+  });
+
+  it("REGRESSION (#5385-sentry, GITTENSORY-1D): a repeat sibling-wake for the SAME unchanged head is still coalesced well past the old 60s window, but a genuinely NEW commit resets the guard", async () => {
+    // Confirmed live: a contributor repeatedly opening (and having auto-closed) near-duplicate PRs re-triggered
+    // the SAME sibling's full review/gate republish every time the cap was recomputed, even though nothing
+    // about the sibling itself ever changed -- one PR published 27 redundant review surfaces in 2 hours this
+    // way. The 60s CI-completion-burst coalesce window was never meant to (and didn't) protect against a
+    // trigger recurring every several minutes to hours.
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: await generatePrivateKeyPem() });
+    await upsertInstallation(env, {
+      installation: { id: 123, account: { login: "JSONbored", id: 1, type: "User" }, target_type: "User", repository_selection: "all", permissions: { metadata: "read", pull_requests: "write", issues: "write" }, events: ["pull_request"] },
+      repositories: [{ name: "gittensory", full_name: "JSONbored/gittensory", private: false, owner: { login: "JSONbored" } }],
+    });
+    await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 54, title: "Farmer PR zero", state: "open", user: { login: "farmer99" }, head: { sha: "f54" }, labels: [], body: "w" });
+    await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 56, title: "Farmer PR two (already over cap)", state: "open", user: { login: "farmer99" }, head: { sha: "f56" }, labels: [], body: "y" });
+    await upsertRepositorySettings(env, {
+      repoFullName: "JSONbored/gittensory",
+      commentMode: "all_prs",
+      publicSurface: "comment_only",
+      checkRunMode: "off",
+      reviewCheckMode: "required",
+      aiReviewMode: "advisory",
+      autonomy: { close: "auto", label: "auto" },
+      contributorOpenPrCap: 2,
+    });
+    const fanned: import("../../src/types").JobMessage[] = [];
+    const realSend = env.JOBS.send.bind(env.JOBS);
+    env.JOBS.send = (async (message: import("../../src/types").JobMessage, options?: QueueSendOptions) => {
+      if (message.type === "agent-regate-pr") fanned.push(message);
+      return realSend(message, options);
+    }) as typeof env.JOBS.send;
+    let pr56Sha = "f56";
+    vi.stubGlobal("fetch", async (input: RequestInfo | URL) => {
+      const url = input.toString();
+      if (url === "https://api.gittensor.io/miners") return Response.json([]);
+      if (url.includes("/access_tokens")) return Response.json({ token: "installation-token" });
+      if (url.includes("/pulls/55/files")) return Response.json([{ filename: "src/a.ts", status: "modified", additions: 1, deletions: 0, changes: 1, patch: "@@\n+const ok = true;" }]);
+      if (url.includes("/pulls/55/reviews")) return Response.json([]);
+      if (url.includes("/pulls/55/commits")) return Response.json([]);
+      // Bare GET /pulls/{54,56} is the sibling live-open-state check the cap computation live-verifies before
+      // treating either as a real, currently-open sibling (#2270 busy-repo bypass fix) -- both must resolve
+      // "open" for PR56 to be correctly identified as the (numerically highest, over-cap) sibling.
+      if (url.endsWith("/pulls/54")) return Response.json({ number: 54, state: "open", user: { login: "farmer99" }, head: { sha: "f54" }, mergeable_state: "clean" });
+      if (url.endsWith("/pulls/56")) return Response.json({ number: 56, state: "open", user: { login: "farmer99" }, head: { sha: pr56Sha }, mergeable_state: "clean" });
+      if (url.endsWith("/pulls/55")) return Response.json({ number: 55, state: "open", user: { login: "farmer99" }, head: { sha: "f55" }, mergeable_state: "clean" });
+      if (url.includes("/commits/f55/check-runs")) return Response.json({ total_count: 0, check_runs: [] });
+      if (url.includes("/commits/f55/status")) return Response.json({ state: "success", statuses: [] });
+      if (url.includes("/issues/55/labels")) return Response.json([]);
+      if (url.includes("/issues/55/comments")) return Response.json([]);
+      return Response.json({});
+    });
+    const rediscoverPr56AsOverCap = (deliveryId: string) =>
+      processJob(env, {
+        type: "github-webhook",
+        deliveryId,
+        eventName: "pull_request",
+        payload: {
+          action: "opened",
+          installation: { id: 123, account: { login: "JSONbored", id: 1, type: "User" } },
+          repository: { name: "gittensory", full_name: "JSONbored/gittensory", private: false, owner: { login: "JSONbored" } },
+          pull_request: { number: 55, title: "Farmer PR one", state: "open", user: { login: "farmer99" }, head: { sha: "f55" }, labels: [], body: "x", mergeable_state: "clean", reviewDecision: "APPROVED" },
+        },
+      });
+
+    // First discovery: PR56 is over cap -- wakes it once.
+    await rediscoverPr56AsOverCap("wake-first");
+    expect(fanned.filter((job) => job.type === "agent-regate-pr" && job.prNumber === 56)).toHaveLength(1);
+
+    // 90 seconds later: past the OLD 60s coalesce window, but well within the new ~30-minute cooldown for an
+    // UNCHANGED head SHA. A second discovery of the SAME still-over-cap sibling must NOT re-wake it.
+    vi.setSystemTime(new Date("2026-05-28T00:01:30.000Z"));
+    await rediscoverPr56AsOverCap("wake-second-still-coalesced");
+    expect(fanned.filter((job) => job.type === "agent-regate-pr" && job.prNumber === 56)).toHaveLength(1); // still just the one
+
+    // PR56 gets a genuinely NEW commit -- the guard must reset for the new head SHA so the sibling still gets
+    // re-evaluated eventually, not stay silenced forever regardless of what actually changes about it.
+    pr56Sha = "f56-v2";
+    await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 56, title: "Farmer PR two (already over cap)", state: "open", user: { login: "farmer99" }, head: { sha: "f56-v2" }, labels: [], body: "y" });
+    await rediscoverPr56AsOverCap("wake-third-after-new-commit");
+    expect(fanned.filter((job) => job.type === "agent-regate-pr" && job.prNumber === 56)).toHaveLength(2); // woken again for the new head
+  });
+
+  it("REGRESSION (#5385-sentry, GITTENSORY-1D): a sibling-wake lookup miss fails OPEN to the bare (headSha-less) key and the shorter 60s window, instead of skipping the wake", async () => {
+    // wakeOverCapSiblingPullRequests re-resolves the sibling's OWN current head SHA via a fresh getPullRequest
+    // lookup (not the already-fetched author-scoped record) so the coalescing key reflects the truly-latest
+    // commit. Force JUST that lookup to miss (as it would for a PR not yet/no-longer tracked locally) while
+    // every other getPullRequest call in this same pass resolves normally -- proving the documented fail-open
+    // fallback (bare key, CI_COALESCE_WINDOW_SECONDS) actually fires instead of silently dropping the wake.
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: await generatePrivateKeyPem() });
+    await upsertInstallation(env, {
+      installation: { id: 123, account: { login: "JSONbored", id: 1, type: "User" }, target_type: "User", repository_selection: "all", permissions: { metadata: "read", pull_requests: "write", issues: "write" }, events: ["pull_request"] },
+      repositories: [{ name: "gittensory", full_name: "JSONbored/gittensory", private: false, owner: { login: "JSONbored" } }],
+    });
+    await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 54, title: "Farmer PR zero", state: "open", user: { login: "farmer99" }, head: { sha: "f54" }, labels: [], body: "w" });
+    await upsertPullRequestFromGitHub(env, "JSONbored/gittensory", { number: 56, title: "Farmer PR two (already over cap)", state: "open", user: { login: "farmer99" }, head: { sha: "f56" }, labels: [], body: "y" });
+    await upsertRepositorySettings(env, {
+      repoFullName: "JSONbored/gittensory",
+      commentMode: "all_prs",
+      publicSurface: "comment_only",
+      checkRunMode: "off",
+      reviewCheckMode: "required",
+      aiReviewMode: "advisory",
+      autonomy: { close: "auto", label: "auto" },
+      contributorOpenPrCap: 2,
+    });
+    const realGetPullRequest = repositoriesModule.getPullRequest;
+    vi.spyOn(repositoriesModule, "getPullRequest").mockImplementation(async (spyEnv, fullName, number) => {
+      if (number === 56) return null; // simulate PR56 not being found locally at wake time
+      return realGetPullRequest(spyEnv, fullName, number);
+    });
+    const setSpy = vi.spyOn(env.SELFHOST_TRANSIENT_CACHE!, "set");
+    const fanned: import("../../src/types").JobMessage[] = [];
+    const realSend = env.JOBS.send.bind(env.JOBS);
+    env.JOBS.send = (async (message: import("../../src/types").JobMessage, options?: QueueSendOptions) => {
+      if (message.type === "agent-regate-pr") fanned.push(message);
+      return realSend(message, options);
+    }) as typeof env.JOBS.send;
+    vi.stubGlobal("fetch", async (input: RequestInfo | URL) => {
+      const url = input.toString();
+      if (url === "https://api.gittensor.io/miners") return Response.json([]);
+      if (url.includes("/access_tokens")) return Response.json({ token: "installation-token" });
+      if (url.includes("/pulls/55/files")) return Response.json([{ filename: "src/a.ts", status: "modified", additions: 1, deletions: 0, changes: 1, patch: "@@\n+const ok = true;" }]);
+      if (url.includes("/pulls/55/reviews")) return Response.json([]);
+      if (url.includes("/pulls/55/commits")) return Response.json([]);
+      if (url.endsWith("/pulls/54")) return Response.json({ number: 54, state: "open", user: { login: "farmer99" }, head: { sha: "f54" }, mergeable_state: "clean" });
+      if (url.endsWith("/pulls/56")) return Response.json({ number: 56, state: "open", user: { login: "farmer99" }, head: { sha: "f56" }, mergeable_state: "clean" });
+      if (url.endsWith("/pulls/55")) return Response.json({ number: 55, state: "open", user: { login: "farmer99" }, head: { sha: "f55" }, mergeable_state: "clean" });
+      if (url.includes("/commits/f55/check-runs")) return Response.json({ total_count: 0, check_runs: [] });
+      if (url.includes("/commits/f55/status")) return Response.json({ state: "success", statuses: [] });
+      if (url.includes("/issues/55/labels")) return Response.json([]);
+      if (url.includes("/issues/55/comments")) return Response.json([]);
+      return Response.json({});
+    });
+
+    await processJob(env, {
+      type: "github-webhook",
+      deliveryId: "sibling-lookup-miss",
+      eventName: "pull_request",
+      payload: {
+        action: "opened",
+        installation: { id: 123, account: { login: "JSONbored", id: 1, type: "User" } },
+        repository: { name: "gittensory", full_name: "JSONbored/gittensory", private: false, owner: { login: "JSONbored" } },
+        pull_request: { number: 55, title: "Farmer PR one", state: "open", user: { login: "farmer99" }, head: { sha: "f55" }, labels: [], body: "x", mergeable_state: "clean", reviewDecision: "APPROVED" },
+      },
+    });
+
+    expect(fanned.some((job) => job.type === "agent-regate-pr" && job.prNumber === 56)).toBe(true); // still woken despite the lookup miss
+    const call = setSpy.mock.calls.find(([key]) => (key as string).startsWith("contributor-cap-wake:jsonbored/gittensory#56"));
+    expect(call?.[0]).toBe("contributor-cap-wake:jsonbored/gittensory#56"); // bare key -- no headSha suffix
+    expect(call?.[2]).toBe(60); // CI_COALESCE_WINDOW_SECONDS, not the ~1800s headSha-keyed cooldown
   });
 
   it("contributor open-ISSUE cap (#2270): a contributor's 3rd open issue (over a cap of 2) is labeled + closed deterministically", async () => {