If I compile a CI command twice using --keep-build-dir I get the following error:

pio ci -b uno --build-dir C:\Users\ll\Desktop\build\test --keep-build-dir C:\Users\ll\Desktop\test\src\test.ino

Error: Traceback (most recent call last):
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\platformio\__main__.py", line 120, in main
    cli(None, None, None)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\core.py", line 700, in __call__
    return self.main(*args, **kwargs)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\core.py", line 680, in main
    rv = self.invoke(ctx)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\core.py", line 1027, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\core.py", line 873, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\core.py", line 508, in invoke
    return callback(*args, **kwargs)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\click\decorators.py", line 16, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\platformio\commands\ci.py", line 99, in cli
    _copy_contents(join(build_dir, dir_name), contents)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\site-packages\platformio\commands\ci.py", line 137, in _copy_contents
    makedirs(dst_dir)
  File "c:\users\ll\appdata\local\programs\python\python37-32\lib\os.py", line 221, in makedirs
    mkdir(name, mode)
FileExistsError: [WinError 183] Cannot create a file when that file already exists: 'C:\\Users\\ll\\Desktop\\build\\test\\src'
============================================================
An unexpected error occurred. Further steps:
* Verify that you have the latest version of PlatformIO using
  `pip install -U platformio` command
* Try to find answer in FAQ Troubleshooting section
  https://docs.platformio.org/page/faq.html
* Report this problem to the developers
  https://github.com/platformio/platformio-core/issues
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Shouldn’t be possible to compile the sketch all the time replacing the file from source? there is a different solution besides to erase the build folder?
Windows 10

PIO: 4.0.0a4