Duplicate label warning

[GlenNicholls]

I am running Sphinx 4.4.0 with sphinx-argparse 0.3.1 and I am seeing the following warning when using subparsers:

/.../api/cli.rst:3: WARNING: duplicate label positional arguments, other instance in /.../api/cli.rst
/.../api/cli.rst:3: WARNING: duplicate label named arguments, other instance in /.../api/cli.rst
/.../api/cli.rst:3: WARNING: duplicate label positional arguments, other instance in /.../api/cli.rst
/.../api/cli.rst:3: WARNING: duplicate label named arguments, other instance in /.../api/cli.rst

In my conf.py, I have enabled sphinx.ext.autosectionlabel for extensions. Here is a MWE of my test case:

import argparse
from pathlib import Path

def clean() -> None:
    pass

def run() -> None:
    pass

def get_argparser() -> argparse.ArgumentParser:
    cwd = Path.cwd().resolve()
    out_dir = cwd / "build"

    parent_parser = argparse.ArgumentParser(add_help=False)
    parent_parser.add_argument(
        "-v",
        "--verbose",
        action="store_true",
        default=False,
        help="Debug log level.",
    )

    parser = argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    subparsers = parser.add_subparsers(dest="subparser_name")

    parser.add_argument(
        "--version",
        action="version",
        version="1.0",
        help="Display the version.",
    )

    # Clean workspace parser
    parser_clean = subparsers.add_parser(
        "clean",
        help="Clean workspace and exit.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser_clean.add_argument(
        "path",
        nargs="*",
        default=out_dir,
        type=Path,
        help="Files and/or directories to permanently remove from the workspace.",
    )
    parser_clean.set_defaults(func=clean)

    # Run subparser
    parser_run = subparsers.add_parser(
        "run",
        parents=[parent_parser],
        help="Run.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser_run.add_argument(
        "--no-backup",
        action="store_true",
        default=False,
        help="Do not maintain timestamped artifacts.",
    )
    parser_run.set_defaults(func=run)

    return parser

I am looking at the docs and it states it handles duplicated header names by appending a number X to the anchor name, but it doesn't appear this is working correctly. Either that or the anchor is ignored because I am using sphinx.ext.autosectionlabel?