diff --git a/litellm/_logging.py b/litellm/_logging.py
index 0ca3cfd730e..a65ba741edb 100644
--- a/litellm/_logging.py
+++ b/litellm/_logging.py
@@ -1016,7 +1016,9 @@ def print_startup_message(message: str) -> None:
     level, whole and unredacted as the print showed it; a blank spacer produces no record.
     """
     if not litellm.json_logs:
-        print(message)  # noqa: T201  # plain mode: this is the operator-terminal print it replaces
+        print(  # noqa: T201  # plain mode: this is the operator-terminal print it replaces
+            REDACTED_BY_LITELLM if diagnostic_message_logging_disabled() else message
+        )
         return
     text: Final = _ANSI_ESCAPE.sub("", message).strip("\n")
     if not text:
diff --git a/litellm/proxy/common_request_processing.py b/litellm/proxy/common_request_processing.py
index ad58809ff97..4420a351263 100644
--- a/litellm/proxy/common_request_processing.py
+++ b/litellm/proxy/common_request_processing.py
@@ -4566,10 +4566,12 @@ class ProxyBaseLLMRequestProcessing:
                 e,
             )
 
+            stream_error_status: Final = error_status_code(e, status.HTTP_500_INTERNAL_SERVER_ERROR)
+            log_safe_diagnostic(
+                verbose_proxy_logger, "request_failed", status_code=stream_error_status, level=logging.ERROR
+            )
             if isinstance(e, HTTPException):
                 raise e
-            stream_error_status: Final = error_status_code(e, status.HTTP_500_INTERNAL_SERVER_ERROR)
-            log_safe_diagnostic(verbose_proxy_logger, "request_failed", status_code=stream_error_status)
             proxy_exception: Final = ProxyException(
                 message=redact_internal_details_from_client_message(getattr(e, "message", str(e))),
                 type=openai_error_type(e, stream_error_status),
diff --git a/tests/unit/integrations/cloudzero/test_cz_stream_api.py b/tests/unit/integrations/cloudzero/test_cz_stream_api.py
index 89a4357494e..326daa3b368 100644
--- a/tests/unit/integrations/cloudzero/test_cz_stream_api.py
+++ b/tests/unit/integrations/cloudzero/test_cz_stream_api.py
@@ -1,3 +1,4 @@
+import json
 import zoneinfo
 from datetime import datetime, timezone
 from typing import Final
@@ -9,8 +10,6 @@ import pytest
 import respx
 
 import litellm
-
-
 from litellm.integrations.cloudzero.cz_stream_api import CloudZeroStreamer
 
 
@@ -198,3 +197,47 @@ def test_cloudzero_http_error_diagnostics_respect_privacy_without_changing_excep
             streamer._send_daily_batch("2026-01-01", pl.DataFrame({"cost/cost": [1.0]}), "replace_hourly")
     assert captured.value.response.text == marker
     assert (marker in capsys.readouterr().out) is not redact
+
+
+@pytest.mark.parametrize("redact", (False, True))
+def test_cloudzero_skips_invalid_timestamp_without_logging_content_when_private(
+    redact: bool, capsys: pytest.CaptureFixture[str], monkeypatch: pytest.MonkeyPatch
+) -> None:
+    monkeypatch.setattr(litellm, "redact_messages_in_debug_logs", redact)
+    marker: Final = "synthetic-private-invalid-timestamp"
+    streamer: Final = CloudZeroStreamer("test-key", "test-connection")
+    data: Final = pl.DataFrame(
+        {"time/usage_start": [marker, "2026-01-01T00:00:00Z"], "cost/cost": [9.0, 1.0]}
+    )
+    with respx.mock:
+        route: Final = respx.post(
+            f"{streamer.base_url}/v2/connections/billing/anycost/test-connection/billing_drops"
+        ).respond(status_code=200)
+        streamer.send_batched(data)
+    assert len(route.calls) == 1
+    assert json.loads(route.calls[0].request.content) == {
+        "month": "2026-01",
+        "operation": "replace_hourly",
+        "data": [{"time/usage_start": "2026-01-01T00:00:00Z", "cost/cost": "1"}],
+    }
+    assert (marker in capsys.readouterr().out) is not redact
+
+
+@pytest.mark.parametrize("redact", (False, True))
+def test_cloudzero_network_error_preserved_without_logging_content_when_private(
+    redact: bool, capsys: pytest.CaptureFixture[str], monkeypatch: pytest.MonkeyPatch
+) -> None:
+    monkeypatch.setattr(litellm, "redact_messages_in_debug_logs", redact)
+    marker: Final = "synthetic-private-network-error"
+    streamer: Final = CloudZeroStreamer("test-key", "test-connection")
+    failure: Final = httpx.ConnectError(marker)
+    with respx.mock:
+        respx.post(
+            f"{streamer.base_url}/v2/connections/billing/anycost/test-connection/billing_drops"
+        ).mock(side_effect=failure)
+        with pytest.raises(httpx.ConnectError) as captured:
+            streamer.send_batched(
+                pl.DataFrame({"time/usage_start": ["2026-01-01T00:00:00Z"], "cost/cost": [1.0]})
+            )
+    assert captured.value is failure
+    assert (marker in capsys.readouterr().out) is not redact
diff --git a/tests/unit/proxy/test_common_request_processing.py b/tests/unit/proxy/test_common_request_processing.py
index 34fd5f79a69..b79d13b5c59 100644
--- a/tests/unit/proxy/test_common_request_processing.py
+++ b/tests/unit/proxy/test_common_request_processing.py
@@ -12249,3 +12249,56 @@ async def test_debug_message_privacy_preserves_stream_content(
         assert all("PRIVATE_STREAM_INPUT_42896" not in message for message in messages)
     else:
         assert any("PRIVATE_STREAM_INPUT_42896" in message for message in messages)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("privacy", [False, True])
+@pytest.mark.parametrize("http_error", [False, True])
+async def test_stream_failure_retains_error_status_without_debug_logging(
+    monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture, privacy: bool, http_error: bool
+) -> None:
+    import logging
+
+    from litellm._logging import verbose_proxy_logger
+
+    monkeypatch.setattr(litellm, "redact_messages_in_debug_logs", privacy)
+    monkeypatch.setattr(litellm, "callbacks", [])
+    monkeypatch.setattr(litellm, "success_callback", [])
+    monkeypatch.setattr(litellm, "_async_success_callback", [])
+    monkeypatch.setattr(litellm, "include_cost_in_streaming_usage", False)
+    monkeypatch.setattr(verbose_proxy_logger, "level", logging.ERROR)
+    ProxyLogging._callback_capabilities_cache.clear()
+    failure: Final = (
+        HTTPException(status_code=429, detail="PRIVATE_STREAM_FAILURE_42896")
+        if http_error
+        else RuntimeError("PRIVATE_STREAM_FAILURE_42896")
+    )
+
+    async def upstream() -> AsyncGenerator[str, None]:
+        yield "data: started\n\n"
+        raise failure
+
+    stream: Final = ProxyBaseLLMRequestProcessing.async_streaming_data_generator(
+        response=upstream(),
+        user_api_key_dict=ProxyUserAPIKeyAuth(),
+        request_data={"model": "example-model"},
+        proxy_logging_obj=ProxyLogging(user_api_key_cache=DualCache()),
+        serialize_chunk=str,
+        serialize_error=str,
+    )
+    assert await anext(stream) == "data: started\n\n"
+    if http_error:
+        with pytest.raises(HTTPException) as raised:
+            await anext(stream)
+        assert raised.value is failure
+    else:
+        remaining: Final = tuple([chunk async for chunk in stream])
+        assert len(remaining) == 1
+        assert "PRIVATE_STREAM_FAILURE_42896" in remaining[0]
+    messages: Final = tuple(record.getMessage() for record in caplog.records if record.name == verbose_proxy_logger.name)
+    if privacy:
+        assert any(f"event=request_failed status={429 if http_error else 500}" in message for message in messages)
+        assert all("PRIVATE_STREAM_FAILURE_42896" not in message for message in messages)
+    else:
+        assert any("PRIVATE_STREAM_FAILURE_42896" in message for message in messages)
+        assert all("event=request_failed" not in message for message in messages)
diff --git a/tests/unit/test_logging.py b/tests/unit/test_logging.py
index e147fc41f7a..b6c2c1926c7 100644
--- a/tests/unit/test_logging.py
+++ b/tests/unit/test_logging.py
@@ -1827,6 +1827,20 @@ def test_print_verbose_formats_args_only_when_set_verbose_is_on(monkeypatch, cap
     assert capsys.readouterr().out == "key k1 value cached-vector\n"
 
 
+@pytest.mark.parametrize("privacy", [False, True])
+@pytest.mark.parametrize("json_logs", [False, True])
+def test_startup_message_respects_diagnostic_privacy(
+    monkeypatch: pytest.MonkeyPatch, capfd: pytest.CaptureFixture[str], privacy: bool, json_logs: bool
+) -> None:
+    monkeypatch.setattr(litellm, "redact_messages_in_debug_logs", privacy)
+    monkeypatch.setattr(litellm, "json_logs", json_logs)
+    print_startup_message("PRIVATE_CONFIGURED_MODEL_42896")
+    out, err = capfd.readouterr()
+    message: Final = json.loads(out)["message"] if json_logs else out.strip()
+    assert message == ("redacted-by-litellm" if privacy else "PRIVATE_CONFIGURED_MODEL_42896")
+    assert err == ""
+
+
 def test_print_startup_message_prints_plain_mode_text_unchanged(
     monkeypatch: pytest.MonkeyPatch, capfd: pytest.CaptureFixture[str]
 ) -> None: