Micromamba: Cannot activate env because cannot initialize shell cmd.exe (corp env)

C:\Users\ACORPUSER>micromamba shell init --shell cmd.exe --root-prefix=%MAMBA_ROOT_PREFIX%
cmd.exe already initialized.
Enter admin mode to enable long paths support?: [y/N] N
Aborted.
warning  libmamba Did not enable long paths support.

C:\Users\ACORPUSER>micromamba activate work4
critical libmamba Shell not initialized

'micromamba' is running as a subprocess and can't modify the parent shell.
Thus you must initialize your shell before using activate and deactivate.

To automatically initialize all future (cmd.exe) shells, run:
    $ micromamba shell init --shell cmd.exe --root-prefix=~/.local/share/mamba
If your shell was already initialized, reinitialize your shell with:
    $ micromamba shell reinit --shell cmd.exe
Otherwise, this may be an issue. In the meantime you can run commands. See:
    $ micromamba run --help

Supported shells are {bash, zsh, csh, posix, xonsh, cmd.exe, powershell, fish, nu}.

C:\Users\ACORPUSER>micromamba shell reinit --shell cmd.exe --root-prefix=%MAMBA_ROOT_PREFIX%
The following arguments were not expected: cmd.exe --shell
Run with --help for more information.

C:\Users\ACORPUSER>echo %MAMBA_ROOT_PREFIX%
C:\Users\ACORPUSER/.conda/envs/mmbase
 
C:\Users\ACORPUSER>micromamba info
       libmamba version : 2.0.4
     micromamba version : 2.0.4
           curl version : libcurl/8.8.0-DEV Schannel zlib/1.3.1
     libarchive version : libarchive 3.7.2 zlib/1.3.1 liblzma/5.6.2 bz2lib/1.0.8 liblz4/1.9.4 libzstd/1.5.6
       envs directories : C:\Users\ACORPUSER\.conda\envs
          package cache : C:\Users\ACORPUSER\.conda\envs\mmbase\pkgs
                          C:\Users\ACORPUSER\.mamba\pkgs
                          C:\Users\ACORPUSER\AppData\Roaming\.mamba\pkgs
            environment : base
           env location : C:\Users\ACORPUSER\.conda\envs\mmbase
      user config files : C:\Users\ACORPUSER\.mambarc
populated config files : C:\Users\ACORPUSER\.mambarc
                          C:\Users\ACORPUSER\.condarc
       virtual packages : __win=10.0.22631=0
                          __archspec=1=x86_64
                          __cuda=12.2=0
               channels : https://corp-artifactory.corp.internal/artifactory/ext-conda-forge-proxy/noarch
                          https://corp-artifactory.corp.internal/artifactory/ext-conda-forge-proxy/win-64
       base environment : C:\Users\ACORPUSER\.conda\envs\mmbase
               platform : win-64

See above

N/A

# this .condarc works: tested successfully with conda (from miniforge)

channel_alias: https://corp-artifactory.corp.internal/artifactory

channels:
- ext-conda-forge-proxy

env_dirs:
- c:\Users\ACORPUSER\.conda\envs

ssl_verify: c:\Users\ACORPUSER\bin\ca-bundle.crt