diff --git a/analyzer/codechecker_analyzer/analyzers/analyzer_types.py b/analyzer/codechecker_analyzer/analyzers/analyzer_types.py
index ccc8946b1b..8bbebe6db6 100644
--- a/analyzer/codechecker_analyzer/analyzers/analyzer_types.py
+++ b/analyzer/codechecker_analyzer/analyzers/analyzer_types.py
@@ -93,8 +93,9 @@ def is_ignore_conflict_supported():
                             .get_env_for_bin(
                                 context.replacer_binary),
                             encoding="utf-8", errors="ignore")
-    out, _ = proc.communicate()
-    return '--ignore-insert-conflict' in out
+    out, err = proc.communicate()
+    help_output = out + err
+    return '--ignore-insert-conflict' in help_output
 
 
 def print_unsupported_analyzers(errored):
diff --git a/analyzer/tests/unit/test_analyzer_types.py b/analyzer/tests/unit/test_analyzer_types.py
new file mode 100644
index 0000000000..277a01685e
--- /dev/null
+++ b/analyzer/tests/unit/test_analyzer_types.py
@@ -0,0 +1,58 @@
+# coding=utf-8
+"""
+Unit tests for analyzer type helper functions.
+"""
+
+from unittest import mock
+
+from codechecker_analyzer.analyzers import analyzer_types
+
+
+class FakeProcess:
+    """Fake subprocess object for clang-apply-replacements --help."""
+
+    def __init__(self, stdout_text, stderr_text):
+        self._stdout_text = stdout_text
+        self._stderr_text = stderr_text
+
+    def communicate(self):
+        return self._stdout_text, self._stderr_text
+
+
+class FakeContext:
+    """Fake analyzer context with a configured replacer binary."""
+
+    replacer_binary = "clang-apply-replacements"
+
+    def get_env_for_bin(self, _binary):
+        return {}
+
+
+def test_ignore_insert_conflict_detected_from_stderr():
+    """The flag should be detected even if help text is printed to stderr."""
+
+    with mock.patch.object(
+        analyzer_types.analyzer_context,
+        "get_context",
+        return_value=FakeContext()
+    ), mock.patch.object(
+        analyzer_types.subprocess,
+        "Popen",
+        return_value=FakeProcess("", "--ignore-insert-conflict")
+    ):
+        assert analyzer_types.is_ignore_conflict_supported()
+
+
+def test_ignore_insert_conflict_detected_from_stdout():
+    """The flag should still be detected from stdout."""
+
+    with mock.patch.object(
+        analyzer_types.analyzer_context,
+        "get_context",
+        return_value=FakeContext()
+    ), mock.patch.object(
+        analyzer_types.subprocess,
+        "Popen",
+        return_value=FakeProcess("--ignore-insert-conflict", "")
+    ):
+        assert analyzer_types.is_ignore_conflict_supported()