diff --git a/tests/unit/test_soak_corpus.py b/tests/unit/test_soak_corpus.py
index 90d05b7..d95ce33 100644
--- a/tests/unit/test_soak_corpus.py
+++ b/tests/unit/test_soak_corpus.py
@@ -242,3 +242,12 @@ class TestLiveInvariantsAndCaps:
         inv_fault_errors_present(rows, fault_source_names=[])  # 未配故障源直接通过
         with pytest.raises(AssertionError):
             inv_fault_errors_present([_row("c")], fault_source_names=["bad_1"])
+
+
+class TestAnyErrors:
+    def test_presence_and_absence(self):
+        from tools.soak.scoreboard import inv_any_errors
+
+        inv_any_errors([_row("a", error="TransientError: x"), _row("b")])
+        with pytest.raises(AssertionError, match="故障未生效"):
+            inv_any_errors([_row("c")])
diff --git a/tools/soak/run_soak.py b/tools/soak/run_soak.py
index c6f5e5a..c3f9302 100644
--- a/tools/soak/run_soak.py
+++ b/tools/soak/run_soak.py
@@ -198,12 +198,11 @@ def _scoreboard(args: argparse.Namespace, env: dict[str, str]) -> None:
         asyncio.run(_live_checks(args, env, verdicts))
     else:
         verdicts.append(("记账归零/gate 可再准入", "SKIP — memory 后端跨进程不可查"))
-    # 不变量 2c: P5/P6 且配置了故障源 → 故障必须真实发生
+    # 不变量 2c: P5/P6 故障混编池下错误必须真实发生。紧闸源被限流闸跳过
+    # 不产错误行、故障名单无法从配置泛化推断 → 钉全局存在性,按源归因
+    # 交报告"错误分布"人工核对(findings §4 条 2 的比例校准留待 P5 常态化)
     if args.scenario in ("P5", "P6"):
-        fault_names = [
-            name for name in rpm_conf if rpm_conf[name] <= 10
-        ]  # 紧闸源;坏 key/黑洞源由错误分布人工核对(findings §4 条 2 校准留待 P5 实跑)
-        _check("故障混编生效(P5/P6)", sb.inv_fault_errors_present, rows, fault_source_names=fault_names)
+        _check("故障混编生效(P5/P6)", sb.inv_any_errors, rows)
     rate = sb.structured_success_rate(rows, session_suffix="-p3")
     verdicts.append(("P3 结构化成功率", f"{rate:.3f}(基线首跑建立)"))
     report = sb.render_report(args.run_id, rows, verdicts)
diff --git a/tools/soak/scoreboard.py b/tools/soak/scoreboard.py
index e6a06c8..b7a47e1 100644
--- a/tools/soak/scoreboard.py
+++ b/tools/soak/scoreboard.py
@@ -179,3 +179,12 @@ def inv_fault_errors_present(rows: list[Row], *, fault_source_names: list[str])
         return
     fault_errors = [r for r in rows if r.get("error") and r["source_name"] in fault_source_names]
     assert fault_errors, f"故障源 {fault_source_names} 零错误行——故障混编未生效"
+
+
+def inv_any_errors(rows: list[Row]) -> None:
+    """不变量 2c 的兜底形态(P5/P6): 故障源混编池下错误行必然存在。
+
+    紧闸源被限流闸跳过不产错误行,故障名单无法从配置泛化推断——按源归因
+    交报告"错误分布"人工核对;此处只钉全局存在性。
+    """
+    assert any(r.get("error") for r in rows), "P5/P6 故障混编池零错误行——故障未生效"