diff --git a/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts b/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
index 6f57084c47a..6c7d85dc709 100644
--- a/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
+++ b/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
@@ -133,7 +133,6 @@ describeEmbeddedPostgres("heartbeat stale queued-run invalidation", () => {
       await new Promise((resolve) => setTimeout(resolve, 50));
     }
     await new Promise((resolve) => setTimeout(resolve, 50));
-    await db.delete(activityLog);
     await db.delete(companySkills);
     await db.delete(issueComments);
     await db.delete(issueDocuments);
@@ -346,6 +345,86 @@ describeEmbeddedPostgres("heartbeat stale queued-run invalidation", () => {
     expect(mockAdapterExecute).not.toHaveBeenCalled();
   });
 
+  it("cancels queued in_review runs when the current participant changes before the run starts", async () => {
+    const { companyId, agentId } = await seedCompanyAndAgent();
+    const otherAgentId = randomUUID();
+    await db.insert(agents).values({
+      id: otherAgentId,
+      companyId,
+      name: "ReviewerAgent",
+      role: "qa",
+      status: "active",
+      adapterType: "codex_local",
+      adapterConfig: {},
+      runtimeConfig: { heartbeat: { wakeOnDemand: true, maxConcurrentRuns: 1 } },
+      permissions: {},
+    });
+
+    const issueId = randomUUID();
+    await db.insert(issues).values({
+      id: issueId,
+      companyId,
+      title: "In-review task now owned by reviewer",
+      status: "in_review",
+      priority: "medium",
+      assigneeAgentId: agentId,
+      executionState: {
+        status: "pending",
+        currentStageId: randomUUID(),
+        currentStageIndex: 0,
+        currentStageType: "review",
+        currentParticipant: { type: "agent", agentId: otherAgentId, userId: null },
+        returnAssignee: { type: "agent", agentId, userId: null },
+        reviewRequest: null,
+        completedStageIds: [],
+        lastDecisionId: null,
+        lastDecisionOutcome: null,
+      },
+    });
+
+    const { runId, wakeupRequestId } = await seedQueuedRun({
+      companyId,
+      agentId,
+      issueId,
+      wakeReason: "issue_assigned",
+    });
+
+    await heartbeat.resumeQueuedRuns();
+
+    await waitForCondition(async () => {
+      const run = await db
+        .select({ status: heartbeatRuns.status })
+        .from(heartbeatRuns)
+        .where(eq(heartbeatRuns.id, runId))
+        .then((rows) => rows[0] ?? null);
+      return run?.status === "cancelled";
+    });
+
+    const [run, wakeup] = await Promise.all([
+      db
+        .select({
+          status: heartbeatRuns.status,
+          errorCode: heartbeatRuns.errorCode,
+          resultJson: heartbeatRuns.resultJson,
+        })
+        .from(heartbeatRuns)
+        .where(eq(heartbeatRuns.id, runId))
+        .then((rows) => rows[0] ?? null),
+      db
+        .select({ status: agentWakeupRequests.status, error: agentWakeupRequests.error })
+        .from(agentWakeupRequests)
+        .where(eq(agentWakeupRequests.id, wakeupRequestId))
+        .then((rows) => rows[0] ?? null),
+    ]);
+
+    expect(run?.status).toBe("cancelled");
+    expect(run?.errorCode).toBe("issue_review_participant_changed");
+    expect(run?.resultJson).toMatchObject({ stopReason: "issue_review_participant_changed" });
+    expect(wakeup?.status).toBe("skipped");
+    expect(wakeup?.error).toContain("in-review participant changed");
+    expect(mockAdapterExecute).not.toHaveBeenCalled();
+  });
+
   it("still runs comment-driven wakes on in_review issues even when the agent is no longer the current participant", async () => {
     const { companyId, agentId } = await seedCompanyAndAgent();
     const otherAgentId = randomUUID();