pipx: Updating Python from 3.9.1_4 to 3.9.1_8 causes No such file or directory

Yesterday, I ran brew upgrade. After that, my shell (xonsh), as installed by pipx, stopped running. It would fail with:

login: /Users/jaraco/.local/bin/xonsh: No such file or directory

So I load up bash and inspect:

$ ls -la ~/.local/pipx/venvs/xonsh/bin/python3.9
lrwxr-xr-x   1 jaraco  primarygroup    69 Jan  5 11:39 python3.9 -> /Users/jaraco/.local/homebrew/Cellar/python@3.9/3.9.1_4/bin/python3.9

It seems python3.9 no longer points to a valid Python, and thus all pipx commands are now broken.

I was able to reinstall-all, which worked, but also emitted an error:

$ pipx reinstall-all
Failed to upgrade shared libraries
Traceback (most recent call last):
  File "/Users/jaraco/.local/homebrew/lib/python3.9/site-packages/pipx/shared_libs.py", line 92, in upgrade
    upgrade_process = run_subprocess(
  File "/Users/jaraco/.local/homebrew/lib/python3.9/site-packages/pipx/util.py", line 123, in run_subprocess
    completed_process = subprocess.run(
  File "/Users/jaraco/.local/homebrew/Cellar/python@3.9/3.9.1_8/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 501, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/Users/jaraco/.local/homebrew/Cellar/python@3.9/3.9.1_8/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 947, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/Users/jaraco/.local/homebrew/Cellar/python@3.9/3.9.1_8/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 1819, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/Users/jaraco/.local/pipx/shared/bin/python'
uninstalled oathtool! ✨ 🌟 ✨
...
done! ✨ 🌟 ✨
$ ls -la ~/.local/pipx/venvs/xonsh/bin/python3.9
lrwxr-xr-x  1 jaraco  primarygroup  69 Feb 19 09:25 /Users/jaraco/.local/pipx/venvs/xonsh/bin/python3.9 -> /Users/jaraco/.local/homebrew/Cellar/python@3.9/3.9.1_8/bin/python3.9

I have pipx 0.16.0.0.

Is it the case that a reinstall-all is expected to be needed between patch updates to Python? I haven’t experienced this issue on my other mac where I have Homebrew installed in the canonical location. Is there anything that one can do to avoid this failure when running brew upgrade?