diff --git a/lib/spack/spack/test/util/unparse/unparse.py b/lib/spack/spack/test/util/unparse/unparse.py
index 986ba7e262c..5c8d5bd9771 100644
--- a/lib/spack/spack/test/util/unparse/unparse.py
+++ b/lib/spack/spack/test/util/unparse/unparse.py
@@ -244,6 +244,7 @@ def check_ast_roundtrip(code1, filename="internal", mode="exec"):
     assert ast.dump(ast1) == ast.dump(ast2), error_msg
 
 
+@pytest.mark.xfail(reason="https://github.com/spack/spack/pull/38424")
 def test_core_lib_files():
     """Roundtrip source files from the Python core libs."""
     test_directories = [