diff --git a/lib/substantive_fixer.py b/lib/substantive_fixer.py
index 6280e55..c7537b0 100644
--- a/lib/substantive_fixer.py
+++ b/lib/substantive_fixer.py
@@ -540,6 +540,7 @@ async def substantive_fix_cycle(conn, max_workers=None) -> tuple[int, int]:
            AND (domain_verdict = 'request_changes' OR leo_verdict = 'request_changes')
            AND COALESCE(fix_attempts, 0) < ?
            AND (last_attempt IS NULL OR last_attempt < datetime('now', '-3 minutes'))
+           AND json_valid(eval_issues)
            AND EXISTS (
                SELECT 1 FROM json_each(eval_issues)
                WHERE value IN ({placeholders})
@@ -552,10 +553,11 @@ async def substantive_fix_cycle(conn, max_workers=None) -> tuple[int, int]:
     if not rows:
         return 0, 0
 
-    # Defense-in-depth: corrupt eval_issues JSON shouldn't reach here (json_each
-    # would error in the SELECT and SQLite would skip the row), but the WARN log
-    # stays so we catch any edge case where a row's JSON parses for json_each
-    # but not for json.loads (different parsers, technically).
+    # Defense-in-depth: json_valid(eval_issues) in the SELECT already filters
+    # corrupt JSON before json_each runs, so this WARN should be unreachable.
+    # Kept anyway: json_valid and json.loads use technically distinct parsers,
+    # and the journal entry names the failure mode if SQLite ever surfaces a
+    # row that passes json_valid + json_each but fails json.loads.
     substantive_rows = []
     for row in rows:
         try: