diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 81acd96..79e1c54 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -12,6 +12,15 @@ The semantic versioning only considers the public API as described in
 paths are considered internals and can change in minor and patch releases.
 
 
+v4.25.1 (2023-10-??)
+--------------------
+
+Fixed
+^^^^^
+- Failures with subcommands and default_config_files when keys are repeated
+  (`#160 <https://github.com/omni-us/jsonargparse/issues/160>`__).
+
+
 v4.25.0 (2023-09-25)
 --------------------
 
diff --git a/jsonargparse/_core.py b/jsonargparse/_core.py
index 778613c..0914993 100644
--- a/jsonargparse/_core.py
+++ b/jsonargparse/_core.py
@@ -616,6 +616,7 @@ class ArgumentParser(ParserDeprecations, ActionsContainer, ArgumentLinking, argp
         cfg_path: Union[str, os.PathLike] = "",
         ext_vars: Optional[dict] = None,
         prev_cfg: Optional[Namespace] = None,
+        key: Optional[str] = None,
     ) -> Namespace:
         """Loads a configuration string into a namespace.
 
@@ -633,6 +634,8 @@ class ArgumentParser(ParserDeprecations, ActionsContainer, ArgumentLinking, argp
             raise TypeError(f"Problems parsing config: {ex}") from ex
         if cfg_dict is None:
             return Namespace()
+        if key and isinstance(cfg_dict, dict):
+            cfg_dict = cfg_dict.get(key, {})
         if not isinstance(cfg_dict, dict):
             raise TypeError(f"Unexpected config: {cfg_str}")
         return self._apply_actions(cfg_dict, prev_cfg=prev_cfg)
@@ -954,9 +957,7 @@ class ArgumentParser(ParserDeprecations, ActionsContainer, ArgumentLinking, argp
         default_config_files = self._get_default_config_files()
         for key, default_config_file in default_config_files:
             with change_to_path_dir(default_config_file), parser_context(parent_parser=self):
-                cfg_file = self._load_config_parser_mode(default_config_file.get_content())
-                if key is not None:
-                    cfg_file = cfg_file.get(key)
+                cfg_file = self._load_config_parser_mode(default_config_file.get_content(), key=key)
                 cfg = self.merge_config(cfg_file, cfg)
                 try:
                     with _ActionPrintConfig.skip_print_config():

diff --git a/jsonargparse_tests/test_subcommands.py b/jsonargparse_tests/test_subcommands.py
index ae46995..a629eb3 100644
--- a/jsonargparse_tests/test_subcommands.py
+++ b/jsonargparse_tests/test_subcommands.py
@@ -212,6 +212,37 @@ def test_subcommand_print_config_default_env(subparser):
     assert yaml.safe_load(out) == {"o": 1}
 
 
+def test_subcommand_default_config_repeated_keys(parser, subparser, tmp_cwd):
+    defaults = tmp_cwd / "defaults.json"
+    defaults.write_text('{"test":{"test":"value"}}')
+    parser.default_config_files = [defaults]
+    subparser.add_argument("--test")
+    subcommands = parser.add_subcommands()
+    subcommands.add_subcommand("test", subparser)
+
+    cfg = parser.parse_args([], with_meta=False)
+    assert cfg == Namespace(subcommand="test", test=Namespace(test="value"))
+    cfg = parser.parse_args(["test", "--test=x"], with_meta=False)
+    assert cfg == Namespace(subcommand="test", test=Namespace(test="x"))
+
+
+def test_subsubcommand_default_config_repeated_keys(parser, subparser, tmp_cwd):
+    defaults = tmp_cwd / "defaults.json"
+    defaults.write_text('{"test":{"test":{"test":"value"}}}')
+    parser.default_config_files = [defaults]
+    subsubparser = ArgumentParser()
+    subsubparser.add_argument("--test")
+    subcommands1 = parser.add_subcommands()
+    subcommands1.add_subcommand("test", subparser)
+    subcommands2 = subparser.add_subcommands()
+    subcommands2.add_subcommand("test", subsubparser)
+
+    cfg = parser.parse_args([], with_meta=False)
+    assert cfg.as_dict() == {"subcommand": "test", "test": {"subcommand": "test", "test": {"test": "value"}}}
+    cfg = parser.parse_args(["test", "test", "--test=x"], with_meta=False)
+    assert cfg.as_dict() == {"subcommand": "test", "test": {"subcommand": "test", "test": {"test": "x"}}}
+
+
 def test_subcommand_required_arg_in_default_config(parser, subparser, tmp_cwd):
     Path("config.yaml").write_text("output: test\nprepare:\n  media: test\n")
     parser.default_config_files = ["config.yaml"]

Repeated Keys in Nested List
This was my first day trying out this module 
I notice that repeated key names may lead to undesirable results. Even if they are separated by level

I have given out some examples I tested out. It really only causes issues for two of them







jsonargparse_tests/test_subcommands.py::test_subcommand_default_config_repeated_keys jsonargparse_tests/test_subcommands.py::test_subsubcommand_default_config_repeated_keys
jsonargparse_tests/test_subcommands.py::test_add_subparsers_not_implemented jsonargparse_tests/test_subcommands.py::test_add_parser_not_implemented jsonargparse_tests/test_subcommands.py::test_subcommands_get_defaults jsonargparse_tests/test_subcommands.py::test_subcommands_undefined_subcommand jsonargparse_tests/test_subcommands.py::test_subcommands_not_given_when_few_subcommands jsonargparse_tests/test_subcommands.py::test_subcommands_not_given_when_many_subcommands jsonargparse_tests/test_subcommands.py::test_subcommands_missing_required_subargument jsonargparse_tests/test_subcommands.py::test_subcommands_undefined_subargument jsonargparse_tests/test_subcommands.py::test_subcommands_parse_args_basics jsonargparse_tests/test_subcommands.py::test_main_subcommands_help jsonargparse_tests/test_subcommands.py::test_subcommands_parse_args_alias jsonargparse_tests/test_subcommands.py::test_subcommands_parse_args_config jsonargparse_tests/test_subcommands.py::test_subcommands_parse_string_implicit_subcommand jsonargparse_tests/test_subcommands.py::test_subcommands_parse_string_first_implicit_subcommand jsonargparse_tests/test_subcommands.py::test_subcommands_parse_string_explicit_subcommand jsonargparse_tests/test_subcommands.py::test_subcommands_parse_args_config_explicit_subcommand_arg jsonargparse_tests/test_subcommands.py::test_subcommands_parse_args_environment jsonargparse_tests/test_subcommands.py::test_subcommands_parse_env jsonargparse_tests/test_subcommands.py::test_subcommands_help_default_env_true jsonargparse_tests/test_subcommands.py::test_subcommand_required_false jsonargparse_tests/test_subcommands.py::test_subcommand_without_options jsonargparse_tests/test_subcommands.py::test_subcommand_print_config_default_env jsonargparse_tests/test_subcommands.py::test_subcommand_required_arg_in_default_config jsonargparse_tests/test_subcommands.py::test_subsubcommands_parse_args jsonargparse_tests/test_subcommands.py::test_subsubcommands_wrong_add_order jsonargparse_tests/test_subcommands.py::test_subcommands_custom_instantiator