diff --git a/litellm/integrations/prometheus.py b/litellm/integrations/prometheus.py
index 08db77e8571..0220676f5da 100644
--- a/litellm/integrations/prometheus.py
+++ b/litellm/integrations/prometheus.py
@@ -1969,8 +1969,8 @@ class PrometheusLogger(CustomLogger):
                 return
 
             api_base = standard_logging_payload["api_base"]
-            _litellm_params = request_kwargs.get("litellm_params", {}) or {}
-            _metadata = get_litellm_metadata_from_kwargs(request_kwargs)
+            _litellm_params = request_kwargs.get("litellm_params") or {}
+            _metadata = get_litellm_metadata_from_kwargs(request_kwargs) or {}
             litellm_model_name = request_kwargs.get("model", None)
             llm_provider = _litellm_params.get("custom_llm_provider", None)
             _model_info = _metadata.get("model_info") or {}
diff --git a/litellm/litellm_core_utils/core_helpers.py b/litellm/litellm_core_utils/core_helpers.py
index 7c8e2ebeaff..76d2d1fed72 100644
--- a/litellm/litellm_core_utils/core_helpers.py
+++ b/litellm/litellm_core_utils/core_helpers.py
@@ -163,7 +163,7 @@ def get_litellm_metadata_from_kwargs(kwargs: dict):
 
     Return `litellm_metadata` if it exists, otherwise return `metadata`
     """
-    litellm_params = kwargs.get("litellm_params", {})
+    litellm_params = kwargs.get("litellm_params") or {}
     if litellm_params:
         metadata = litellm_params.get("metadata", {})
         litellm_metadata = litellm_params.get("litellm_metadata", {})
diff --git a/litellm/router_strategy/lowest_latency.py b/litellm/router_strategy/lowest_latency.py
index 0449a843bd2..07f38965dac 100644
--- a/litellm/router_strategy/lowest_latency.py
+++ b/litellm/router_strategy/lowest_latency.py
@@ -87,7 +87,11 @@ class LowestLatencyLoggingHandler(CustomLogger):
                         kwargs.get("completion_start_time", end_time) - start_time
                     )
 
-                final_value: Union[float, timedelta] = response_ms
+                # Always convert to float seconds for Redis JSON serialization
+                if isinstance(response_ms, timedelta):
+                    final_value: Union[float, timedelta] = response_ms.total_seconds()
+                else:
+                    final_value: Union[float, timedelta] = float(response_ms) if response_ms else 0.0
                 time_to_first_token: Optional[float] = None
                 total_tokens = 0
 
@@ -308,7 +312,11 @@ class LowestLatencyLoggingHandler(CustomLogger):
                         kwargs.get("completion_start_time", end_time) - start_time
                     )
 
-                final_value: Union[float, timedelta] = response_ms
+                # Always convert to float seconds for Redis JSON serialization
+                if isinstance(response_ms, timedelta):
+                    final_value: Union[float, timedelta] = response_ms.total_seconds()
+                else:
+                    final_value: Union[float, timedelta] = float(response_ms) if response_ms else 0.0
                 total_tokens = 0
                 time_to_first_token: Optional[float] = None