diff --git a/tests/acceptance/conftest.py b/tests/acceptance/conftest.py
index 45662aa..f3d3dc0 100644
--- a/tests/acceptance/conftest.py
+++ b/tests/acceptance/conftest.py
@@ -150,7 +150,20 @@ def ir_data(ir_path: str) -> dict:
     from step3_merge_and_audit import _normalize_rule
     rules = data.get("rules", [])
     if rules:
-        data["rules"] = [_normalize_rule(r) for r in rules]
+        normalized = []
+        for i, r in enumerate(rules):
+            if not isinstance(r, dict):
+                continue  # Skip non-dict entries defensively
+            # Defensive: flatten list-type section fields (LLM produces these sometimes)
+            for src in r.get("sources", []):
+                sec = src.get("section")
+                if isinstance(sec, list):
+                    src["section"] = sec[0] if sec else ""
+            try:
+                normalized.append(_normalize_rule(r))
+            except Exception:
+                normalized.append(r)  # Fallback: use raw rule if normalize crashes
+        data["rules"] = normalized
 
     return data