diff --git a/.gitignore b/.gitignore
index 5523c93..6074f74 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,10 @@ output/badges/
 output/.badge-gist-id
 # Stable flock inode used to serialize security coverage receipt readers/writers.
 output/.github-security-coverage-latest.json.lock
+# Stable flock inode used to serialize portfolio truth publishers.
+output/.portfolio-truth-latest.json.lock
+# Local run output written by PortfolioCommandCenter before truth publication.
+output/pcc-auditor-run.log
 # Generated private portfolio dumps written to the repo ROOT (chmod 600). The
 # output/*.md rule above does not cover root-level files, so name them explicitly
 # to keep a stray `git add -A` from committing private portfolio data.
diff --git a/src/github_repo_auditor/portfolio_decision_queue.py b/src/github_repo_auditor/portfolio_decision_queue.py
index c16db3d..0bacbf8 100644
--- a/src/github_repo_auditor/portfolio_decision_queue.py
+++ b/src/github_repo_auditor/portfolio_decision_queue.py
@@ -15,6 +15,7 @@
 import json
 import sys
 from datetime import datetime, timedelta, timezone
+from functools import partial
 from pathlib import Path
 from typing import Any
 
@@ -26,6 +27,7 @@
     sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
 
 from github_repo_auditor.security_admission import derive_security_admission
+from github_repo_auditor.timestamps import parse_utc_timestamp
 
 CONTRACT_VERSION = "decision_queue_v2"
 DIGEST_CONTRACT_VERSION = "portfolio_decision_digest_v2"
@@ -78,17 +80,7 @@ def _sha256_identity(value: Any) -> str:
     return SHA256_ID_PREFIX + hashlib.sha256(_canonical_bytes(value)).hexdigest()
 
 
-def _parse_datetime(value: Any) -> datetime | None:
-    text = _text(value)
-    if not text:
-        return None
-    try:
-        parsed = datetime.fromisoformat(text.replace("Z", "+00:00"))
-    except ValueError:
-        return None
-    if parsed.tzinfo is None:
-        parsed = parsed.replace(tzinfo=timezone.utc)
-    return parsed.astimezone(timezone.utc)
+_parse_datetime = partial(parse_utc_timestamp, naive="assume_utc")
 
 
 def _iso(value: datetime) -> str:
diff --git a/src/github_repo_auditor/security_admission.py b/src/github_repo_auditor/security_admission.py
index f1a3650..960902b 100644
--- a/src/github_repo_auditor/security_admission.py
+++ b/src/github_repo_auditor/security_admission.py
@@ -3,9 +3,11 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import datetime, timezone
+from datetime import datetime
 from typing import Any, Mapping
 
+from github_repo_auditor.timestamps import parse_utc_timestamp
+
 
 SECURITY_ADMISSION_SCHEMA_VERSION = "SecurityAdmissionV1"
 SECURITY_PROVIDERS = ("dependabot", "code_scanning", "secret_scanning")
@@ -31,17 +33,7 @@ def _text(value: Any) -> str:
     return value.strip() if isinstance(value, str) else ""
 
 
-def _parse_datetime(value: Any) -> datetime | None:
-    text = _text(value)
-    if not text:
-        return None
-    try:
-        parsed = datetime.fromisoformat(text.replace("Z", "+00:00"))
-    except ValueError:
-        return None
-    if parsed.tzinfo is None:
-        return None
-    return parsed.astimezone(timezone.utc)
+_parse_datetime = parse_utc_timestamp
 
 
 def _reason_provider(provider: str, suffix: str) -> str:
diff --git a/src/github_repo_auditor/timestamps.py b/src/github_repo_auditor/timestamps.py
new file mode 100644
index 0000000..0dcc5b0
--- /dev/null
+++ b/src/github_repo_auditor/timestamps.py
@@ -0,0 +1,32 @@
+"""Shared lenient timestamp parsing helpers."""
+
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Literal
+
+
+def parse_utc_timestamp(
+    value: object,
+    *,
+    naive: Literal["reject", "assume_utc"] = "reject",
+    coerce: bool = False,
+) -> datetime | None:
+    """Parse a timestamp and normalize timezone-aware results to UTC."""
+    if coerce:
+        text = str(value or "").strip()
+    elif isinstance(value, str):
+        text = value.strip()
+    else:
+        return None
+    if not text:
+        return None
+    try:
+        parsed = datetime.fromisoformat(text.replace("Z", "+00:00"))
+    except ValueError:
+        return None
+    if parsed.tzinfo is None:
+        if naive == "reject":
+            return None
+        parsed = parsed.replace(tzinfo=timezone.utc)
+    return parsed.astimezone(timezone.utc)
diff --git a/src/github_repo_auditor/weekly_command_center.py b/src/github_repo_auditor/weekly_command_center.py
index 1ed8f44..3296328 100644
--- a/src/github_repo_auditor/weekly_command_center.py
+++ b/src/github_repo_auditor/weekly_command_center.py
@@ -1,7 +1,8 @@
 from __future__ import annotations
 
 import json
-from datetime import datetime, timezone
+from datetime import datetime
+from functools import partial
 from pathlib import Path
 from typing import Any
 
@@ -14,6 +15,7 @@
 )
 from github_repo_auditor.report_enrichment import build_weekly_review_pack
 from github_repo_auditor.security_admission import derive_security_admission
+from github_repo_auditor.timestamps import parse_utc_timestamp
 
 CONTRACT_VERSION = "weekly_command_center_digest_v1"
 AUTHORITY_CAP = "bounded-automation"
@@ -131,17 +133,11 @@ def _mapping(value: Any) -> dict[str, Any]:
     return {}
 
 
-def _parse_datetime(value: Any) -> datetime | None:
-    text = _safe_text(value)
-    if not text:
-        return None
-    try:
-        parsed = datetime.fromisoformat(text.replace("Z", "+00:00"))
-    except ValueError:
-        return None
-    if parsed.tzinfo is None:
-        return parsed.replace(tzinfo=timezone.utc)
-    return parsed.astimezone(timezone.utc)
+_parse_datetime = partial(
+    parse_utc_timestamp,
+    naive="assume_utc",
+    coerce=True,
+)
 
 
 def _source_freshness(
diff --git a/tests/test_producer_preflight.py b/tests/test_producer_preflight.py
index ce907ae..74e5944 100644
--- a/tests/test_producer_preflight.py
+++ b/tests/test_producer_preflight.py
@@ -70,6 +70,40 @@ def test_canonical_producer_fails_dirty_worktree(tmp_path: Path) -> None:
     assert result.checks["worktree_clean"] == "fail"
 
 
+def test_publication_runtime_files_preserve_clean_producer(tmp_path: Path) -> None:
+    from github_repo_auditor.portfolio_truth_publish import (
+        _portfolio_truth_publication_lock,
+    )
+
+    repo, _ = _repo(tmp_path)
+    _git(repo, "config", "core.excludesFile", "/dev/null")
+    (repo / ".gitignore").write_bytes(
+        (Path(__file__).resolve().parents[1] / ".gitignore").read_bytes()
+    )
+    _git(repo, "add", ".gitignore")
+    _git(repo, "commit", "-m", "producer ignore rules")
+    _git(repo, "update-ref", "refs/remotes/origin/main", "HEAD")
+    result = inspect_canonical_producer(
+        repo_root=repo,
+        expected_repository="saagpatel/GithubRepoAuditor",
+        expected_ref="refs/remotes/origin/main",
+        checkout_role="portfolio-command-center",
+    )
+    assert result.state == "pass"
+    assert result.evidence is not None
+    output = repo / "output"
+    output.mkdir()
+    (output / "pcc-auditor-run.log").write_text("running\n")
+    with _portfolio_truth_publication_lock(output / "portfolio-truth-latest.json"):
+        verify_evidence_still_current(repo, result.evidence)
+    verify_evidence_still_current(repo, result.evidence)
+    assert (output / ".portfolio-truth-latest.json.lock").is_file()
+
+    (output / "unexpected-source.py").write_text("changed = True\n")
+    with pytest.raises(ValueError, match="worktree"):
+        verify_evidence_still_current(repo, result.evidence)
+
+
 def test_canonical_producer_missing_ref_is_unknown(tmp_path: Path) -> None:
     repo, _ = _repo(tmp_path)
     result = inspect_canonical_producer(
diff --git a/tests/test_timestamps.py b/tests/test_timestamps.py
new file mode 100644
index 0000000..3da0aaa
--- /dev/null
+++ b/tests/test_timestamps.py
@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+import pytest
+
+from github_repo_auditor.timestamps import parse_utc_timestamp
+
+
+def test_z_suffix_is_treated_as_utc() -> None:
+    assert parse_utc_timestamp("2026-09-02T12:34:56Z") == datetime(
+        2026, 9, 2, 12, 34, 56, tzinfo=timezone.utc
+    )
+
+
+def test_explicit_offset_is_converted_to_utc() -> None:
+    parsed = parse_utc_timestamp("2026-09-02T01:30:00+02:30")
+
+    assert parsed == datetime(
+        2026, 9, 1, 23, 0, tzinfo=timezone.utc
+    )
+    assert parsed.tzinfo is timezone.utc
+
+
+def test_naive_timestamp_is_rejected_by_default() -> None:
+    assert parse_utc_timestamp("2026-09-02T12:34:56") is None
+
+
+def test_naive_timestamp_can_be_assumed_utc() -> None:
+    assert parse_utc_timestamp(
+        "2026-09-02T12:34:56", naive="assume_utc"
+    ) == datetime(2026, 9, 2, 12, 34, 56, tzinfo=timezone.utc)
+
+
+@pytest.mark.parametrize("value", [None, "", "   "])
+@pytest.mark.parametrize("coerce", [False, True])
+def test_empty_values_return_none(value: object, coerce: bool) -> None:
+    assert parse_utc_timestamp(value, coerce=coerce) is None
+
+
+def test_non_string_is_rejected_without_coercion() -> None:
+    value = datetime(2026, 9, 2, 12, 34, 56, tzinfo=timezone.utc)
+
+    assert parse_utc_timestamp(value) is None
+
+
+def test_non_string_can_be_coerced_before_parsing() -> None:
+    value = datetime(2026, 9, 2, 12, 34, 56, tzinfo=timezone.utc)
+
+    assert parse_utc_timestamp(value, coerce=True) == value
+
+
+def test_invalid_string_returns_none() -> None:
+    assert parse_utc_timestamp("not-a-timestamp") is None