diff --git a/ops/quant-monitor/scripts/sync_lifecycle_artifacts.py b/ops/quant-monitor/scripts/sync_lifecycle_artifacts.py
index 57168403..688d7a90 100644
--- a/ops/quant-monitor/scripts/sync_lifecycle_artifacts.py
+++ b/ops/quant-monitor/scripts/sync_lifecycle_artifacts.py
@@ -867,17 +867,41 @@ def _sync_domain(
         now=now,
         max_age=max_age,
     )
-    version_dir, manifest = _load_or_download_version(
-        selected,
-        config,
-        artifacts_root=artifacts_root,
-    )
-    activate_version(
-        version_dir,
-        config,
-        projects_root=projects_root,
-        lifecycle_root=lifecycle_root,
-    )
+    cached_version = artifacts_root / "versions" / config["domain"] / str(selected["id"])
+    try:
+        version_dir, manifest = _load_or_download_version(
+            selected,
+            config,
+            artifacts_root=artifacts_root,
+        )
+    except LifecycleArtifactError as exc:
+        if exc.code == "artifact_invalid" and exc.reason_code == exc.code:
+            stage_reason = (
+                "stored_artifact_validation_failed"
+                if os.path.lexists(cached_version)
+                else "artifact_version_validation_failed"
+            )
+            raise LifecycleArtifactError(
+                "lifecycle artifact version validation failed",
+                code=exc.code,
+                reason_code=stage_reason,
+            ) from exc
+        raise
+    try:
+        activate_version(
+            version_dir,
+            config,
+            projects_root=projects_root,
+            lifecycle_root=lifecycle_root,
+        )
+    except LifecycleArtifactError as exc:
+        if exc.code == "artifact_invalid" and exc.reason_code == exc.code:
+            raise LifecycleArtifactError(
+                "lifecycle artifact activation failed",
+                code=exc.code,
+                reason_code="artifact_activation_failed",
+            ) from exc
+        raise
     created_at = _parse_timestamp(selected["created_at"])
     return {
         "status": "ready",
diff --git a/ops/quant-monitor/tests/test_lifecycle_artifact_sync.py b/ops/quant-monitor/tests/test_lifecycle_artifact_sync.py
index 44a13a2f..7f0766aa 100644
--- a/ops/quant-monitor/tests/test_lifecycle_artifact_sync.py
+++ b/ops/quant-monitor/tests/test_lifecycle_artifact_sync.py
@@ -8,7 +8,7 @@
 import zipfile
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
-
+from unittest.mock import patch
 
 ROOT = Path(__file__).resolve().parents[1]
 
@@ -337,6 +337,110 @@ def test_detects_tampered_stored_version(self) -> None:
             with self.assertRaises(SYNC.LifecycleArtifactError):
                 SYNC.validate_stored_version(version, manifest, self.config)
 
+    def test_sync_domain_classifies_artifact_validation_stage_without_leaking_detail(self) -> None:
+        selected = {
+            "id": 12,
+            "name": "lifecycle-preflight-34-1",
+            "created_at": self.now.isoformat(),
+            "_created_at": self.now.isoformat(),
+            "_trusted_run": {"id": 34, "head_sha": "a" * 40},
+        }
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            secret_detail = "local/path/value must not appear"
+            with (
+                patch.object(SYNC, "_run_gh", return_value={"artifacts": []}),
+                patch.object(SYNC, "select_trusted_artifact", return_value=selected),
+                patch.object(
+                    SYNC,
+                    "_load_or_download_version",
+                    side_effect=SYNC.LifecycleArtifactError(secret_detail),
+                ),
+                self.assertRaises(SYNC.LifecycleArtifactError) as context,
+            ):
+                SYNC._sync_domain(
+                    self.config,
+                    artifacts_root=root / "artifacts",
+                    projects_root=root / "projects",
+                    lifecycle_root=root / "lifecycle",
+                    max_age=timedelta(days=7),
+                    now=self.now,
+                )
+
+            status = SYNC._domain_error_status(context.exception)
+            self.assertEqual(status["code"], "artifact_invalid")
+            self.assertEqual(status["reason_code"], "artifact_version_validation_failed")
+            self.assertNotIn(secret_detail, json.dumps(status))
+
+    def test_sync_domain_distinguishes_cached_version_and_activation_failures(self) -> None:
+        selected = {
+            "id": 12,
+            "name": "lifecycle-preflight-34-1",
+            "created_at": self.now.isoformat(),
+            "_created_at": self.now.isoformat(),
+            "_trusted_run": {"id": 34, "head_sha": "a" * 40},
+        }
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            cached_version = root / "artifacts" / "versions" / self.config["domain"] / "12"
+            cached_version.mkdir(parents=True)
+            with (
+                patch.object(SYNC, "_run_gh", return_value={"artifacts": []}),
+                patch.object(SYNC, "select_trusted_artifact", return_value=selected),
+                patch.object(
+                    SYNC,
+                    "_load_or_download_version",
+                    side_effect=SYNC.LifecycleArtifactError("synthetic cache mismatch"),
+                ),
+                self.assertRaises(SYNC.LifecycleArtifactError) as context,
+            ):
+                SYNC._sync_domain(
+                    self.config,
+                    artifacts_root=root / "artifacts",
+                    projects_root=root / "projects",
+                    lifecycle_root=root / "lifecycle",
+                    max_age=timedelta(days=7),
+                    now=self.now,
+                )
+            self.assertEqual(
+                SYNC._domain_error_status(context.exception)["reason_code"],
+                "stored_artifact_validation_failed",
+            )
+
+            with (
+                patch.object(SYNC, "_run_gh", return_value={"artifacts": []}),
+                patch.object(SYNC, "select_trusted_artifact", return_value=selected),
+                patch.object(
+                    SYNC,
+                    "_load_or_download_version",
+                    return_value=(root / "version", {"profiles": []}),
+                ),
+                patch.object(
+                    SYNC,
+                    "activate_version",
+                    side_effect=SYNC.LifecycleArtifactError("synthetic activation failure"),
+                ),
+                self.assertRaises(SYNC.LifecycleArtifactError) as context,
+            ):
+                SYNC._sync_domain(
+                    self.config,
+                    artifacts_root=root / "fresh-artifacts",
+                    projects_root=root / "projects",
+                    lifecycle_root=root / "lifecycle",
+                    max_age=timedelta(days=7),
+                    now=self.now,
+                )
+            self.assertEqual(
+                SYNC._domain_error_status(context.exception)["reason_code"],
+                "artifact_activation_failed",
+            )
+
+    def test_unexpected_domain_error_remains_safe_and_generic(self) -> None:
+        status = SYNC._domain_error_status(ValueError("secret path and content"))
+        self.assertEqual(status["code"], "artifact_sync_unexpected")
+        self.assertEqual(status["reason_code"], "artifact_sync_unexpected")
+        self.assertNotIn("secret path", json.dumps(status))
+
     def test_classify_gh_api_rate_limit_without_leaking_stderr(self) -> None:
         secret = "ghs_this_is_not_a_real_token_leak_check"
         classified = SYNC.classify_gh_api_failure(