diff --git a/app/utils/logging_utils.py b/app/utils/logging_utils.py
index ec6ff903..a2b4d205 100644
--- a/app/utils/logging_utils.py
+++ b/app/utils/logging_utils.py
@@ -35,9 +35,14 @@ def format(self, record: logging.LogRecord) -> str:
             Formatted log message including ANSI color codes.
         """
 
+        original_levelname = record.levelname
         level_color = self.COLORS.get(record.levelno, "")
-        record.levelname = f"{level_color}{record.levelname}{self.RESET}"
-        return super().format(record)
+        if level_color:
+            record.levelname = f"{level_color}{record.levelname}{self.RESET}"
+        try:
+            return super().format(record)
+        finally:
+            record.levelname = original_levelname
 
 
 class RateLimitFilter(logging.Filter):
diff --git a/tests/test_color_formatter.py b/tests/test_color_formatter.py
index a491d291..f9bcb0f8 100644
--- a/tests/test_color_formatter.py
+++ b/tests/test_color_formatter.py
@@ -24,6 +24,37 @@ def test_format_includes_ansi_codes(self):
         self.assertIn("\033[", output)
         self.assertIn("boom", output)
 
+    def test_plain_handler_is_uncolored_with_colored_sibling(self):
+        logger = logging.getLogger("color_test_plain")
+        colored_stream = io.StringIO()
+        plain_stream = io.StringIO()
+        colored_handler = logging.StreamHandler(colored_stream)
+        colored_handler.setFormatter(ColorFormatter("%(levelname)s:%(message)s"))
+        plain_handler = logging.StreamHandler(plain_stream)
+        plain_handler.setFormatter(logging.Formatter("%(levelname)s:%(message)s"))
+        logger.setLevel(logging.INFO)
+        original_propagate = logger.propagate
+        logger.propagate = False
+        logger.addHandler(colored_handler)
+        logger.addHandler(plain_handler)
+
+        try:
+            logger.warning("mixed output")
+        finally:
+            logger.removeHandler(colored_handler)
+            logger.removeHandler(plain_handler)
+            colored_handler.close()
+            plain_handler.close()
+            logger.propagate = original_propagate
+
+        colored_output = colored_stream.getvalue().strip()
+        plain_output = plain_stream.getvalue().strip()
+
+        self.assertIn("\033[", colored_output)
+        self.assertIn("mixed output", colored_output)
+        self.assertNotIn("\033[", plain_output)
+        self.assertIn("mixed output", plain_output)
+
 
 if __name__ == "__main__":
     unittest.main()