diff --git a/shared/logging/src/airflow_shared/logging/percent_formatter.py b/shared/logging/src/airflow_shared/logging/percent_formatter.py
index ee9195e59b594..0efbb78d9922e 100644
--- a/shared/logging/src/airflow_shared/logging/percent_formatter.py
+++ b/shared/logging/src/airflow_shared/logging/percent_formatter.py
@@ -55,6 +55,12 @@ def __getitem__(self, key):
         # https://github.com/python/cpython/blob/d3c888b4ec15dbd7d6b6ef4f15b558af77c228af/Lib/logging/__init__.py#L1652C34-L1652C48
         if key == "lineno":
             return self.event.get("lineno") or 0
+        # process and thread are numeric callsite params formatted with %d, so fall back to a
+        # number (like lineno above) rather than the "(unknown)" string used for text params;
+        # otherwise "%(process)d"/"%(thread)d" raises TypeError when the callsite info is absent
+        # (e.g. warnings routed through the logging bridge).
+        if key == "process" or key == "thread":
+            return self.event.get(key) or 0
         if key == "filename":
             return self.event.get("filename", "(unknown file)")
         if key == "funcName":
diff --git a/shared/logging/tests/logging/test_percent_formatter.py b/shared/logging/tests/logging/test_percent_formatter.py
index 3a3ae84f562eb..217c23708e5e2 100644
--- a/shared/logging/tests/logging/test_percent_formatter.py
+++ b/shared/logging/tests/logging/test_percent_formatter.py
@@ -19,6 +19,8 @@
 
 from unittest import mock
 
+import pytest
+
 from airflow_shared.logging.percent_formatter import PercentFormatRender
 
 
@@ -40,3 +42,19 @@ def test_lineno_is_none(self):
         )
 
         assert formatted == "test.py:0 our msg"
+
+    @pytest.mark.parametrize(
+        "event",
+        [
+            pytest.param({"event": "our msg"}, id="missing"),
+            pytest.param({"event": "our msg", "process": None, "thread": None}, id="none"),
+        ],
+    )
+    def test_numeric_callsite_without_process_or_thread(self, event):
+        # Regression for a scheduler crash: a %d specifier for process/thread with no callsite
+        # info (e.g. a warning routed through the logging bridge) must not raise TypeError.
+        fmter = PercentFormatRender("%(process)d:%(thread)d %(message)s")
+
+        formatted = fmter(mock.Mock(name="Logger"), "info", event)
+
+        assert formatted == "0:0 our msg"