Conda environments are no longer isolated

Anaconda has become completely broken on my Ubuntu server. In any conda environment, I can import packages all that I installed in my base environment, at a minimum. For example I have a package ctha_xml that comes from a private GitHub repository belonging to my company. I can run:

conda create -n foo python=3.9
conda activate foo
python
  >>> import ctha_xml

and it works, because ctha_xml is installed in my base environment. This applies to all packages in my base environment, and all environments besides base.

What can I do to fix this? Could this be something wrong with my environment variables or my .bashrc?

os.environ inside a conda environment called text-generation-client looks like this:

environ{'SHELL': '/bin/bash',
        'CONDA_EXE': '/opt/conda/bin/conda',
        '_CE_M': '',
        'PWD': '/home/holmes',
        'LOGNAME': 'holmes',
        'XDG_SESSION_TYPE': 'tty',
        'CONDA_PREFIX': '/home/holmes/.conda/envs/text-generation-client',
        'MOTD_SHOWN': 'pam',
        'HOME': '/home/holmes',
        'LANG': 'C.UTF-8',
        'LS_COLORS': 'rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:',
        'CONDA_PROMPT_MODIFIER': '(text-generation-client) ',
        'LC_TERMINAL': 'iTerm2',
        'SSH_CONNECTION': '10.159.5.25 44390 10.60.244.9 22',
        'LESSCLOSE': '/usr/bin/lesspipe %s %s',
        'XDG_SESSION_CLASS': 'user',
        'TERM': 'xterm-256color',
        '_CE_CONDA': '',
        'LESSOPEN': '| /usr/bin/lesspipe %s',
        'USER': 'holmes',
        'CONDA_SHLVL': '2',
        'LC_TERMINAL_VERSION': '3.4.19',
        'SHLVL': '1',
        'XDG_SESSION_ID': '2383',
        'CONDA_PYTHON_EXE': '/opt/conda/bin/python',
        'XDG_RUNTIME_DIR': '/run/user/1001',
        'SSH_CLIENT': '10.159.5.25 44390 22',
        'CONDA_DEFAULT_ENV': 'text-generation-client',
        'XDG_DATA_DIRS': '/usr/local/share:/usr/share:/var/lib/snapd/desktop',
        'PATH': '/home/holmes/.conda/envs/text-generation-client/bin:/opt/conda/condabin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/holmes/bin',
        'DBUS_SESSION_BUS_ADDRESS': 'unix:path=/run/user/1001/bus',
        'SSH_TTY': '/dev/pts/8',
        'CONDA_PREFIX_1': '/opt/conda',
        '_': '/home/holmes/.conda/envs/text-generation-client/bin/ipython',
        'KMP_DUPLICATE_LIB_OK': 'True',
        'KMP_INIT_AT_FORK': 'FALSE'}

ctha_xml.__file__ indicates that it is being loaded from

/home/holmes/.local/lib/python3.10/site-packages/ctha_xml/__init__.py

Based on this GitHub issue, I learned that I can run

conda install -c conda-forge conda-ecosystem-user-package-isolation

to solve this problem. You will need to deactivate and activate your environment afterwards, or you will not be able to import any packages. One can also set PYTHONNOUSERSITE=1, but that messes up the base environment if you set it globally.

I still don't understand why this behavior suddenly started happening when it wasn't happening before, or why conda doesn't do the equivalent of the operation I mentioned on every new environment, but the effort of installing one package on each environment is very minimal, so I'm happy with this solution.