diff --git a/litellm/llms/custom_httpx/llm_http_handler.py b/litellm/llms/custom_httpx/llm_http_handler.py
index 27791f034bb..a38988b2e38 100644
--- a/litellm/llms/custom_httpx/llm_http_handler.py
+++ b/litellm/llms/custom_httpx/llm_http_handler.py
@@ -939,12 +939,20 @@ class BaseLLMHTTPHandler:
             sync_httpx_client = client
 
         try:
-            response = sync_httpx_client.post(
-                url=api_base,
-                headers=headers,
-                data=signed_body if signed_body is not None else json.dumps(data),
-                timeout=timeout,
-            )
+            if signed_body is not None:
+                response = sync_httpx_client.post(
+                    url=api_base,
+                    headers=headers,
+                    data=signed_body,
+                    timeout=timeout,
+                )
+            else:
+                response = sync_httpx_client.post(
+                    url=api_base,
+                    headers=headers,
+                    json=data,
+                    timeout=timeout,
+                )
         except Exception as e:
             raise self._handle_error(
                 e=e,
diff --git a/litellm/llms/oci/chat/cohere.py b/litellm/llms/oci/chat/cohere.py
index 0ffa685a9f2..d5d136d179d 100644
--- a/litellm/llms/oci/chat/cohere.py
+++ b/litellm/llms/oci/chat/cohere.py
@@ -216,8 +216,15 @@ def handle_cohere_response(
         finish_reason = "length"
     elif oci_finish_reason == "TOOL_CALL":
         finish_reason = "tool_calls"
+    elif oci_finish_reason is not None:
+        # OCI Cohere can emit error/cancel finish reasons (e.g. ``ERROR``,
+        # ``ERROR_TOXIC``, ``ERROR_LIMIT``, ``USER_CANCEL``) that aren't part
+        # of OpenAI's standard set. Normalize them to ``"stop"`` so downstream
+        # consumers switching on ``finish_reason`` keep working — matches the
+        # streaming handler below.
+        finish_reason = "stop"
     else:
-        finish_reason = oci_finish_reason
+        finish_reason = None
 
     tool_calls: Optional[List[Dict[str, Any]]] = None
     if cohere_response.chatResponse.toolCalls:
diff --git a/litellm/llms/oci/chat/generic.py b/litellm/llms/oci/chat/generic.py
index c860c3fefd5..e0700ca2ead 100644
--- a/litellm/llms/oci/chat/generic.py
+++ b/litellm/llms/oci/chat/generic.py
@@ -332,7 +332,11 @@ def handle_generic_response(
     elif oci_finish_reason == "TOOL_CALLS":
         model_response.choices[0].finish_reason = "tool_calls"  # type: ignore[union-attr]
     elif oci_finish_reason is not None:
-        model_response.choices[0].finish_reason = oci_finish_reason  # type: ignore[union-attr,assignment]
+        # OCI GENERIC can emit non-OpenAI finish reasons (e.g. ``ERROR``,
+        # ``CONTENT_FILTERED``, ``CANCELLED``). Normalize to ``"stop"`` so
+        # downstream consumers switching on ``finish_reason`` keep working —
+        # matches the streaming handler.
+        model_response.choices[0].finish_reason = "stop"  # type: ignore[union-attr]
 
     oci_usage = completion_response.chatResponse.usage
     reasoning_tokens: Optional[int] = None
@@ -398,8 +402,13 @@ def handle_generic_stream_chunk(dict_chunk: dict) -> ModelResponseStream:
         finish_reason = "length"
     elif oci_finish_reason == "TOOL_CALLS":
         finish_reason = "tool_calls"
+    elif oci_finish_reason is not None:
+        # OCI GENERIC can emit non-OpenAI finish reasons (e.g. ``ERROR``,
+        # ``CONTENT_FILTERED``, ``CANCELLED``). Normalize to ``"stop"`` so
+        # downstream consumers switching on ``finish_reason`` keep working.
+        finish_reason = "stop"
     else:
-        finish_reason = oci_finish_reason
+        finish_reason = None
 
     return ModelResponseStream(
         choices=[
diff --git a/litellm/llms/oci/chat/transformation.py b/litellm/llms/oci/chat/transformation.py
index 1bf960e5efc..740292dbc74 100644
--- a/litellm/llms/oci/chat/transformation.py
+++ b/litellm/llms/oci/chat/transformation.py
@@ -252,6 +252,12 @@ class OCIChatConfig(BaseConfig):
                 adapted_params[key] = value
                 continue
             adapted_params[alias] = value
+            # Preserve the original OpenAI ``response_format`` key alongside the
+            # OCI-mapped ``responseFormat`` so downstream litellm framework code
+            # (e.g. ``json_mode`` detection, logging) that inspects
+            # ``optional_params["response_format"]`` continues to work.
+            if alias == "responseFormat":
+                adapted_params["response_format"] = value
 
         return adapted_params