diff --git a/litellm/llms/bedrock/count_tokens/transformation.py b/litellm/llms/bedrock/count_tokens/transformation.py
index f1cc1a33f94..df042a4da73 100644
--- a/litellm/llms/bedrock/count_tokens/transformation.py
+++ b/litellm/llms/bedrock/count_tokens/transformation.py
@@ -208,8 +208,7 @@ class BedrockCountTokensConfig(BaseAWSLLM):
             else messages
         )
         body_data: Final = {  # mutable-ok: outbound JSON body, defaults are set below like before
-            **{k: v for k, v in request_data.items() if k not in ("model", "messages")},  # mutable-ok: spread source
-            **({"messages": sanitized_messages} if "messages" in request_data else {}),  # mutable-ok: spread source
+            k: (sanitized_messages if k == "messages" else v) for k, v in request_data.items() if k != "model"
         }
 
         if "messages" in body_data:
diff --git a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
index d687fa79234..b7ba135feca 100644
--- a/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
+++ b/litellm/llms/bedrock/messages/invoke_transformations/anthropic_claude3_transformation.py
@@ -652,18 +652,23 @@ class AmazonAnthropicClaudeMessagesConfig(
                     sanitized.offenders,
                     model,
                 )
-                anthropic_messages_request["messages"] = list(sanitized.messages)  # mutable-ok: outbound JSON array
+                anthropic_messages_request["messages"] = list(  # rebind-ok: out-param  # mutable-ok: json
+                    sanitized.messages
+                )
         thinking: Final = anthropic_messages_request.get("thinking")
+        if not isinstance(thinking, dict):
+            return
         normalized_thinking: Final = normalize_bedrock_invoke_thinking_display(
             thinking, supported_display_values=self.BEDROCK_INVOKE_SUPPORTED_THINKING_DISPLAY_VALUES
         )
-        if normalized_thinking is not thinking:
-            verbose_logger.warning(
-                "Bedrock Invoke: mapping unsupported thinking.display %r to 'summarized' for model=%s",
-                thinking.get("display") if isinstance(thinking, dict) else thinking,
-                model,
-            )
-            anthropic_messages_request["thinking"] = normalized_thinking
+        if normalized_thinking is thinking:
+            return
+        verbose_logger.warning(
+            "Bedrock Invoke: mapping unsupported thinking.display %r to 'summarized' for model=%s",
+            thinking.get("display"),
+            model,
+        )
+        anthropic_messages_request["thinking"] = normalized_thinking  # rebind-ok: out-param
 
     def _strip_unsupported_bedrock_invoke_fields(
         self,
diff --git a/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py b/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
index 0a03fa0e157..7630e760f8c 100644
--- a/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
+++ b/tests/test_litellm/llms/bedrock/messages/invoke_transformations/test_anthropic_claude3_transformation.py
@@ -3558,9 +3558,17 @@ def test_bedrock_invoke_rejects_message_emptied_by_stripping():
     assert "messages[1]" in str(exc.value)
 
     already_empty: Final = _transform_for_bedrock_invoke(
-        [{"role": "user", "content": "hi"}, {"role": "assistant", "content": []}, {"role": "user", "content": "go"}]
+        [
+            {"role": "user", "content": "hi", "output_config": {"effort": "low"}},
+            {"role": "assistant", "content": []},
+            {"role": "user", "content": [_TOOL_ADDITION_BLOCK, {"type": "text", "text": "go"}]},
+        ]
     )
-    assert already_empty["messages"][1]["content"] == []
+    assert already_empty["messages"] == [
+        {"role": "user", "content": "hi"},
+        {"role": "assistant", "content": []},
+        {"role": "user", "content": [{"type": "text", "text": "go"}]},
+    ]
 
 
 def test_bedrock_invoke_maps_thinking_display_updates_to_summarized():
diff --git a/tests/test_litellm/llms/bedrock/test_bedrock_common_utils.py b/tests/test_litellm/llms/bedrock/test_bedrock_common_utils.py
index 117814a41ff..86e5f01e5b3 100644
--- a/tests/test_litellm/llms/bedrock/test_bedrock_common_utils.py
+++ b/tests/test_litellm/llms/bedrock/test_bedrock_common_utils.py
@@ -550,6 +550,38 @@ def test_strip_unsupported_output_config_keeps_format_drops_effort(local_model_c
     assert body["output_config"] == {"format": schema_format}
 
 
+def test_sanitize_bedrock_invoke_messages_forwards_malformed_entries_next_to_an_offender():
+    from litellm.llms.bedrock.common_utils import (
+        BEDROCK_INVOKE_UNSUPPORTED_CONTENT_BLOCK_TYPES,
+        BEDROCK_INVOKE_UNSUPPORTED_MESSAGE_KEYS,
+        sanitize_bedrock_invoke_messages,
+    )
+
+    raw_string_block = "not a block dict"
+    non_dict_message = "not a message dict"
+    tool_addition = {"type": "tool_addition", "tool_reference": {"type": "tool_reference", "tool_name": "Read"}}
+    messages = [
+        {"role": "user", "content": [raw_string_block, {"type": "text", "text": "hi"}]},
+        non_dict_message,
+        {"role": "assistant", "content": [tool_addition, {"type": "text", "text": "ok"}]},
+    ]
+
+    sanitized = sanitize_bedrock_invoke_messages(
+        messages,
+        unsupported_keys=BEDROCK_INVOKE_UNSUPPORTED_MESSAGE_KEYS,
+        unsupported_block_types=BEDROCK_INVOKE_UNSUPPORTED_CONTENT_BLOCK_TYPES,
+    )
+
+    assert sanitized.offenders == ("messages[2].content[0] (type 'tool_addition')",)
+    assert sanitized.emptied == ()
+    assert list(sanitized.messages) == [
+        {"role": "user", "content": [raw_string_block, {"type": "text", "text": "hi"}]},
+        non_dict_message,
+        {"role": "assistant", "content": [{"type": "text", "text": "ok"}]},
+    ]
+    assert sanitized.messages[1] is non_dict_message
+
+
 def test_apply_structured_output_prefers_legacy_output_format(local_model_cost_map):
     """The legacy ``output_format`` wins over ``output_config.format`` when a
     request carries both, matching the pre-existing precedence."""
diff --git a/tests/unit/llms/bedrock/count_tokens/test_bedrock_count_tokens_transformation.py b/tests/unit/llms/bedrock/count_tokens/test_bedrock_count_tokens_transformation.py
index fde18b51a50..f0153ab995b 100644
--- a/tests/unit/llms/bedrock/count_tokens/test_bedrock_count_tokens_transformation.py
+++ b/tests/unit/llms/bedrock/count_tokens/test_bedrock_count_tokens_transformation.py
@@ -302,21 +302,22 @@ def test_transform_to_invoke_model_format_leaves_clean_anthropic_body_unchanged(
     config = BedrockCountTokensConfig()
     request = {
         "model": "us.anthropic.claude-sonnet-4-6",
-        "system": "be brief",
         "messages": [
             {"role": "user", "content": [{"type": "text", "text": "hi"}]},
             {"role": "assistant", "content": [{"type": "text", "text": "hello"}]},
         ],
+        "system": "be brief",
     }
 
     body = _decoded_invoke_body(config.transform_anthropic_to_bedrock_count_tokens(request))
 
     assert body == {
-        "system": "be brief",
         "messages": request["messages"],
+        "system": "be brief",
         "anthropic_version": "bedrock-2023-05-31",
         "max_tokens": DEFAULT_ANTHROPIC_INVOKE_MODEL_MAX_TOKENS,
     }
+    assert list(body) == ["messages", "system", "anthropic_version", "max_tokens"]
 
 
 def test_transform_anthropic_to_bedrock_request_string_content_still_uses_converse():