diff --git a/solstone/think/surfaces/health.py b/solstone/think/surfaces/health.py
index 29aa14e36..ab281c5bb 100644
--- a/solstone/think/surfaces/health.py
+++ b/solstone/think/surfaces/health.py
@@ -411,6 +411,9 @@ def _scan_talent_day_indexes_for_24h_window(
     problems: dict[str, list[str]] = {}
     cutoff = generated_at - _DAY_MS
 
+    # Talent day indexes are keyed by content day (cortex's request["day"]), so
+    # a run executed in this window can live under an arbitrarily old filename.
+    # The row ts is the only reliable boundary for the 24h health counts.
     # Health intentionally ignores non-day-index root files; retention scans them
     # separately so it can explain why deletion was declined.
     for path in sorted(talents_dir.glob("*.jsonl")):
diff --git a/tests/test_log_retention.py b/tests/test_log_retention.py
index c5e609696..20100e22a 100644
--- a/tests/test_log_retention.py
+++ b/tests/test_log_retention.py
@@ -396,6 +396,14 @@ def test_ac8_ac9_talent_logs_indexes_and_malformed_names(journal):
     assert "malformed_date" in reasons
     assert "malformed_talent_index_row" in reasons
     assert "unreadable_talent_index" in reasons
+    error_paths = {error["path"] for error in result.errors}
+    malformed_paths = {
+        error["path"]
+        for error in result.errors
+        if error["reason"] == "malformed_talent_index_row"
+    }
+    assert old_malformed_index.relative_to(journal).as_posix() in malformed_paths
+    assert recent_index.relative_to(journal).as_posix() not in error_paths
 
 
 def test_ac10_ac11_symlink_unlinked_only_and_cache_mtime_day_logged(journal):