diff --git a/verifiers/utils/message_utils.py b/verifiers/utils/message_utils.py
index 492ce0584..ba74f3891 100644
--- a/verifiers/utils/message_utils.py
+++ b/verifiers/utils/message_utils.py
@@ -37,10 +37,16 @@ def _normalize_raw_message_content(message: dict[str, Any]) -> dict[str, Any]:
     if isinstance(content, list):
         normalized_parts = []
         for part in content:
-            if isinstance(part, dict):
-                normalized_parts.append(from_raw_content_part(part))
-            else:
-                normalized_parts.append(part)
+            if isinstance(part, str):
+                # HuggingFace datasets may serialize content-part dicts to JSON
+                # strings when storing heterogeneous lists in Arrow tables.
+                try:
+                    part = json.loads(part)
+                except (json.JSONDecodeError, TypeError):
+                    pass
+            if isinstance(part, dict) and "type" in part:
+                part = from_raw_content_part(part)
+            normalized_parts.append(part)
         message = dict(message)
         message["content"] = normalized_parts
     return message