diff --git a/backend/backend/settings/base.py b/backend/backend/settings/base.py
index 7593305fdd..970b5fac6a 100644
--- a/backend/backend/settings/base.py
+++ b/backend/backend/settings/base.py
@@ -15,10 +15,17 @@
 from urllib.parse import quote
 
 import httpx
+from django.core.validators import URLValidator
 from dotenv import find_dotenv, load_dotenv
 from utils.common_utils import CommonUtils
 from utils.cors_origin import normalize_web_app_origin
 
+# Django 5.0+ caps URLValidator at 2048 chars. S3 pre-signed URLs signed with
+# temporary/STS credentials (carrying X-Amz-Security-Token) routinely exceed this,
+# causing "Enter a valid URL." on the API deployment `presigned_urls` field.
+# Raise the cap globally. No-op on Django 4.2.x (no such attribute is checked).
+URLValidator.max_length = 8192
+
 missing_settings = []
 
 
diff --git a/workers/executor/executors/legacy_executor.py b/workers/executor/executors/legacy_executor.py
index eae4d05b2f..ce7fbea0d1 100644
--- a/workers/executor/executors/legacy_executor.py
+++ b/workers/executor/executors/legacy_executor.py
@@ -703,6 +703,19 @@ def _failure(child_result: ExecutionResult) -> ExecutionResult:
         )
 
         output_map = structured_output.get(PSKeys.OUTPUT, {}) or {}
+        if not isinstance(output_map, dict):
+            # Single-pass can return a non-dict (e.g. a top-level JSON array) when the
+            # LLM emits a truncated/runaway response. Fail clearly instead of crashing
+            # on .values(), and keep the malformed shape from flowing downstream as a
+            # success.
+            return ExecutionResult.failure(
+                error=(
+                    f"Single-pass extraction returned a {type(output_map).__name__}, "
+                    "expected a field map; the LLM likely produced a truncated or "
+                    "runaway response (check output-token usage)."
+                ),
+                metadata={"usage_records": pipeline_records},
+            )
         answered = sum(1 for v in output_map.values() if v not in (None, "", [], {}))
         shim.stream_log(f"Pipeline completed: {answered}/{len(outputs)} prompts answered")
         out_metadata = {